Jam Jelly Class Lecture
Transcript of Jam Jelly Class Lecture
Pectin Substances-Plant Gums
Pectin is a polymer of α-Galacturonic acid with a variable number of methyl ester groups
Methylated ester of Polygalacturonic acid
Chains of 300 to 1000 glalacturonic acid units
Joined with 1αrarr4 linkages
This structure shown here is three methyl ester forms (-COOCH3) for every
two carboxyl groups (-COOH)
hence it is has a 60 degree of esterification normally called a DE-60 pectin
The Degree of Esterification (DE) affects the gelling properties of pectin
Pectic Substance Nomenclature
1048721Protopectin
ndash Immature plant material
1048721Pectinic acid
ndash Mature plant material
1048721Pectin
ndash Mature plant material
1048721Pectic Acid
ndash Overripe plant material
1048721 Protopectin- high methyl ester content1048721 Pectinic acid-intermediate methyl ester content solublendash Salts are pectinates1048721 Pectin-intermediate methyl ester content colloidal1048721 Pectic Acid-little methyl ester contentndash Salts are pectates
Proto-pectin reaches its maximum quantity in fruits just before picking
time During ripening it is changed by enzymes into pectin and pectinic
acid and finally into pectic acid
It can be readily understood how the fruits become softer and more
juicy as the adhesive between the cells breaks down
The only substance which enters into jelly formation is pectin and it is
therefore of paramount importance to obtain and preserve as much of this
from the fruit as possible
The fruit should be in sound condition and not over ripe so that when the
fruit is cooked in the factory as much pectin as possible is obtained
As the amount and quality of the pectin obtained is extremely variable it
is common practice in order to produce a uniform product to add during
manufacture pectin extracts of standardized strength obtained from apples
or citrus fruits
Pectin dissolves in water Due to the high water content of the fruit mass
a hydration layer is formed around the pectin molecules Therefore the
pectin molecules can not move freely and can not come close enough to
each other to bind Underripe fruits have more pectin as fruit ripens the pectin changes to a non-gelling form
Besides this the free carboxyl groups are dissociated H+ is loosened
a negative end is the result This results in a negative charge of pectin
molecules A negative charge makes the molecules depart from each
other Binding is impossible
Sugar binds water and takes water from the hydration layer
Hydration layer gets thinner and the pectin molecules can move more
freely But the negative charge is actually still very high so the
molecules keep pushing off each other When the acid is added the pH
drops under 35 The positive hydrogen molecules bind the dissociated
groups The negative charge gets more neutral and the pectin molecule
can approach each other so they can bind at several places (The pectin
conglomerates and forms a network of fibers traps the fruit juice or
other liquid much like a sponge absorbs water) This enables a gel to
form
The optimum sugar concentration is about 675 per cent although with
increased pectin and acid jellies can be formed with 60 per cent sugar
Normally 05 per cent to 10 per cent pectin is used in jam
manufacture
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar has the property of stabilizing the
supersaturated solution of sucrose and so reducing the tendency to grain
(discourages sugar crystallization in the jelly)
In the right proportion pectin sugar and acid will form a gel in the
cold This is not possible with cooked pulp without driving off a
considerable amount of the water present This is done after the addition
of sugar by boiling in steam jacketed pans
Sweet spreads (The term sweet spreads covers a wide variety of
products in which the main ingredients are sugar and fruit)
ndashbutters jellies jams conserves marmalades and preservesndashadd zest
to meals They can be made from fruit that is not completely suitable for
canning or freezing All contain the four essential ingredients needed to make a jellied
fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of
different ingredients method of preparation and density of the fruit
pulp Jam and jelly are two different types of fruit preserves (Fruit
preserves are fruits or vegetables that have been prepared and
canned for long term storage)
and the difference between jam and jelly is actually quite significant
in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the
contents Jam is made from whole fruit (fruit pulp) meaning every edible
part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more
evenly-textured spread Because jam includes whole fruit it tends to have more of the
vitamins and minerals found in the parent fruit and it is also usually
only made with one type of fruit whereas jellies may involve a blend
of juices There is also a difference between jam and jelly in terms of
preparation methods
Jam is made by cooking fruit with sugar and water until the fruit
starts to soften and break up releasing its natural pectin Pectin is the
substance which makes jam firm up into a gelatinous solid Once the
fruit is softened the jam can be canned and sealed with some cooks
processing their jam to make the texture more uniform
Jelly can be made with fruit juice or with liquid leftover from
making jam Because whole fruit is not involved pectin must be
added to jelly to ensure that it firms Unlike jelly jam does not need
added pectin illustrating a major difference between jam and jelly
Today the general definition for marmalade is a sweet jelly in
which pieces of fruit and rind are suspended The key is the rind
which gives lends a bitterness to delightfully balance the sweetness
of the jelly Most marmalades have a citrus base either orange
(preferably Seville orange) lime lemon grapefruit or kumquat
FRUIT AND ITS PREPARATION
Important considerations in jam making
Type or variety of fruit
Conditions of the fruit
Suitability for transport and in preparation
Pectin content
High pectin fruits are apples crab apples quinces red currants
gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots
cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-
pectin fruits or with a commercial pectin When a commercial pectin is
added fully ripe fruit can be used The use of this added pectin also
increases the yield from a recipe
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
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- Slide 29
- Slide 30
-
Pectic Substance Nomenclature
1048721Protopectin
ndash Immature plant material
1048721Pectinic acid
ndash Mature plant material
1048721Pectin
ndash Mature plant material
1048721Pectic Acid
ndash Overripe plant material
1048721 Protopectin- high methyl ester content1048721 Pectinic acid-intermediate methyl ester content solublendash Salts are pectinates1048721 Pectin-intermediate methyl ester content colloidal1048721 Pectic Acid-little methyl ester contentndash Salts are pectates
Proto-pectin reaches its maximum quantity in fruits just before picking
time During ripening it is changed by enzymes into pectin and pectinic
acid and finally into pectic acid
It can be readily understood how the fruits become softer and more
juicy as the adhesive between the cells breaks down
The only substance which enters into jelly formation is pectin and it is
therefore of paramount importance to obtain and preserve as much of this
from the fruit as possible
The fruit should be in sound condition and not over ripe so that when the
fruit is cooked in the factory as much pectin as possible is obtained
As the amount and quality of the pectin obtained is extremely variable it
is common practice in order to produce a uniform product to add during
manufacture pectin extracts of standardized strength obtained from apples
or citrus fruits
Pectin dissolves in water Due to the high water content of the fruit mass
a hydration layer is formed around the pectin molecules Therefore the
pectin molecules can not move freely and can not come close enough to
each other to bind Underripe fruits have more pectin as fruit ripens the pectin changes to a non-gelling form
Besides this the free carboxyl groups are dissociated H+ is loosened
a negative end is the result This results in a negative charge of pectin
molecules A negative charge makes the molecules depart from each
other Binding is impossible
Sugar binds water and takes water from the hydration layer
Hydration layer gets thinner and the pectin molecules can move more
freely But the negative charge is actually still very high so the
molecules keep pushing off each other When the acid is added the pH
drops under 35 The positive hydrogen molecules bind the dissociated
groups The negative charge gets more neutral and the pectin molecule
can approach each other so they can bind at several places (The pectin
conglomerates and forms a network of fibers traps the fruit juice or
other liquid much like a sponge absorbs water) This enables a gel to
form
The optimum sugar concentration is about 675 per cent although with
increased pectin and acid jellies can be formed with 60 per cent sugar
Normally 05 per cent to 10 per cent pectin is used in jam
manufacture
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar has the property of stabilizing the
supersaturated solution of sucrose and so reducing the tendency to grain
(discourages sugar crystallization in the jelly)
In the right proportion pectin sugar and acid will form a gel in the
cold This is not possible with cooked pulp without driving off a
considerable amount of the water present This is done after the addition
of sugar by boiling in steam jacketed pans
Sweet spreads (The term sweet spreads covers a wide variety of
products in which the main ingredients are sugar and fruit)
ndashbutters jellies jams conserves marmalades and preservesndashadd zest
to meals They can be made from fruit that is not completely suitable for
canning or freezing All contain the four essential ingredients needed to make a jellied
fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of
different ingredients method of preparation and density of the fruit
pulp Jam and jelly are two different types of fruit preserves (Fruit
preserves are fruits or vegetables that have been prepared and
canned for long term storage)
and the difference between jam and jelly is actually quite significant
in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the
contents Jam is made from whole fruit (fruit pulp) meaning every edible
part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more
evenly-textured spread Because jam includes whole fruit it tends to have more of the
vitamins and minerals found in the parent fruit and it is also usually
only made with one type of fruit whereas jellies may involve a blend
of juices There is also a difference between jam and jelly in terms of
preparation methods
Jam is made by cooking fruit with sugar and water until the fruit
starts to soften and break up releasing its natural pectin Pectin is the
substance which makes jam firm up into a gelatinous solid Once the
fruit is softened the jam can be canned and sealed with some cooks
processing their jam to make the texture more uniform
Jelly can be made with fruit juice or with liquid leftover from
making jam Because whole fruit is not involved pectin must be
added to jelly to ensure that it firms Unlike jelly jam does not need
added pectin illustrating a major difference between jam and jelly
Today the general definition for marmalade is a sweet jelly in
which pieces of fruit and rind are suspended The key is the rind
which gives lends a bitterness to delightfully balance the sweetness
of the jelly Most marmalades have a citrus base either orange
(preferably Seville orange) lime lemon grapefruit or kumquat
FRUIT AND ITS PREPARATION
Important considerations in jam making
Type or variety of fruit
Conditions of the fruit
Suitability for transport and in preparation
Pectin content
High pectin fruits are apples crab apples quinces red currants
gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots
cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-
pectin fruits or with a commercial pectin When a commercial pectin is
added fully ripe fruit can be used The use of this added pectin also
increases the yield from a recipe
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
The only substance which enters into jelly formation is pectin and it is
therefore of paramount importance to obtain and preserve as much of this
from the fruit as possible
The fruit should be in sound condition and not over ripe so that when the
fruit is cooked in the factory as much pectin as possible is obtained
As the amount and quality of the pectin obtained is extremely variable it
is common practice in order to produce a uniform product to add during
manufacture pectin extracts of standardized strength obtained from apples
or citrus fruits
Pectin dissolves in water Due to the high water content of the fruit mass
a hydration layer is formed around the pectin molecules Therefore the
pectin molecules can not move freely and can not come close enough to
each other to bind Underripe fruits have more pectin as fruit ripens the pectin changes to a non-gelling form
Besides this the free carboxyl groups are dissociated H+ is loosened
a negative end is the result This results in a negative charge of pectin
molecules A negative charge makes the molecules depart from each
other Binding is impossible
Sugar binds water and takes water from the hydration layer
Hydration layer gets thinner and the pectin molecules can move more
freely But the negative charge is actually still very high so the
molecules keep pushing off each other When the acid is added the pH
drops under 35 The positive hydrogen molecules bind the dissociated
groups The negative charge gets more neutral and the pectin molecule
can approach each other so they can bind at several places (The pectin
conglomerates and forms a network of fibers traps the fruit juice or
other liquid much like a sponge absorbs water) This enables a gel to
form
The optimum sugar concentration is about 675 per cent although with
increased pectin and acid jellies can be formed with 60 per cent sugar
Normally 05 per cent to 10 per cent pectin is used in jam
manufacture
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar has the property of stabilizing the
supersaturated solution of sucrose and so reducing the tendency to grain
(discourages sugar crystallization in the jelly)
In the right proportion pectin sugar and acid will form a gel in the
cold This is not possible with cooked pulp without driving off a
considerable amount of the water present This is done after the addition
of sugar by boiling in steam jacketed pans
Sweet spreads (The term sweet spreads covers a wide variety of
products in which the main ingredients are sugar and fruit)
ndashbutters jellies jams conserves marmalades and preservesndashadd zest
to meals They can be made from fruit that is not completely suitable for
canning or freezing All contain the four essential ingredients needed to make a jellied
fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of
different ingredients method of preparation and density of the fruit
pulp Jam and jelly are two different types of fruit preserves (Fruit
preserves are fruits or vegetables that have been prepared and
canned for long term storage)
and the difference between jam and jelly is actually quite significant
in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the
contents Jam is made from whole fruit (fruit pulp) meaning every edible
part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more
evenly-textured spread Because jam includes whole fruit it tends to have more of the
vitamins and minerals found in the parent fruit and it is also usually
only made with one type of fruit whereas jellies may involve a blend
of juices There is also a difference between jam and jelly in terms of
preparation methods
Jam is made by cooking fruit with sugar and water until the fruit
starts to soften and break up releasing its natural pectin Pectin is the
substance which makes jam firm up into a gelatinous solid Once the
fruit is softened the jam can be canned and sealed with some cooks
processing their jam to make the texture more uniform
Jelly can be made with fruit juice or with liquid leftover from
making jam Because whole fruit is not involved pectin must be
added to jelly to ensure that it firms Unlike jelly jam does not need
added pectin illustrating a major difference between jam and jelly
Today the general definition for marmalade is a sweet jelly in
which pieces of fruit and rind are suspended The key is the rind
which gives lends a bitterness to delightfully balance the sweetness
of the jelly Most marmalades have a citrus base either orange
(preferably Seville orange) lime lemon grapefruit or kumquat
FRUIT AND ITS PREPARATION
Important considerations in jam making
Type or variety of fruit
Conditions of the fruit
Suitability for transport and in preparation
Pectin content
High pectin fruits are apples crab apples quinces red currants
gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots
cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-
pectin fruits or with a commercial pectin When a commercial pectin is
added fully ripe fruit can be used The use of this added pectin also
increases the yield from a recipe
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Besides this the free carboxyl groups are dissociated H+ is loosened
a negative end is the result This results in a negative charge of pectin
molecules A negative charge makes the molecules depart from each
other Binding is impossible
Sugar binds water and takes water from the hydration layer
Hydration layer gets thinner and the pectin molecules can move more
freely But the negative charge is actually still very high so the
molecules keep pushing off each other When the acid is added the pH
drops under 35 The positive hydrogen molecules bind the dissociated
groups The negative charge gets more neutral and the pectin molecule
can approach each other so they can bind at several places (The pectin
conglomerates and forms a network of fibers traps the fruit juice or
other liquid much like a sponge absorbs water) This enables a gel to
form
The optimum sugar concentration is about 675 per cent although with
increased pectin and acid jellies can be formed with 60 per cent sugar
Normally 05 per cent to 10 per cent pectin is used in jam
manufacture
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar has the property of stabilizing the
supersaturated solution of sucrose and so reducing the tendency to grain
(discourages sugar crystallization in the jelly)
In the right proportion pectin sugar and acid will form a gel in the
cold This is not possible with cooked pulp without driving off a
considerable amount of the water present This is done after the addition
of sugar by boiling in steam jacketed pans
Sweet spreads (The term sweet spreads covers a wide variety of
products in which the main ingredients are sugar and fruit)
ndashbutters jellies jams conserves marmalades and preservesndashadd zest
to meals They can be made from fruit that is not completely suitable for
canning or freezing All contain the four essential ingredients needed to make a jellied
fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of
different ingredients method of preparation and density of the fruit
pulp Jam and jelly are two different types of fruit preserves (Fruit
preserves are fruits or vegetables that have been prepared and
canned for long term storage)
and the difference between jam and jelly is actually quite significant
in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the
contents Jam is made from whole fruit (fruit pulp) meaning every edible
part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more
evenly-textured spread Because jam includes whole fruit it tends to have more of the
vitamins and minerals found in the parent fruit and it is also usually
only made with one type of fruit whereas jellies may involve a blend
of juices There is also a difference between jam and jelly in terms of
preparation methods
Jam is made by cooking fruit with sugar and water until the fruit
starts to soften and break up releasing its natural pectin Pectin is the
substance which makes jam firm up into a gelatinous solid Once the
fruit is softened the jam can be canned and sealed with some cooks
processing their jam to make the texture more uniform
Jelly can be made with fruit juice or with liquid leftover from
making jam Because whole fruit is not involved pectin must be
added to jelly to ensure that it firms Unlike jelly jam does not need
added pectin illustrating a major difference between jam and jelly
Today the general definition for marmalade is a sweet jelly in
which pieces of fruit and rind are suspended The key is the rind
which gives lends a bitterness to delightfully balance the sweetness
of the jelly Most marmalades have a citrus base either orange
(preferably Seville orange) lime lemon grapefruit or kumquat
FRUIT AND ITS PREPARATION
Important considerations in jam making
Type or variety of fruit
Conditions of the fruit
Suitability for transport and in preparation
Pectin content
High pectin fruits are apples crab apples quinces red currants
gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots
cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-
pectin fruits or with a commercial pectin When a commercial pectin is
added fully ripe fruit can be used The use of this added pectin also
increases the yield from a recipe
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
The optimum sugar concentration is about 675 per cent although with
increased pectin and acid jellies can be formed with 60 per cent sugar
Normally 05 per cent to 10 per cent pectin is used in jam
manufacture
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar has the property of stabilizing the
supersaturated solution of sucrose and so reducing the tendency to grain
(discourages sugar crystallization in the jelly)
In the right proportion pectin sugar and acid will form a gel in the
cold This is not possible with cooked pulp without driving off a
considerable amount of the water present This is done after the addition
of sugar by boiling in steam jacketed pans
Sweet spreads (The term sweet spreads covers a wide variety of
products in which the main ingredients are sugar and fruit)
ndashbutters jellies jams conserves marmalades and preservesndashadd zest
to meals They can be made from fruit that is not completely suitable for
canning or freezing All contain the four essential ingredients needed to make a jellied
fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of
different ingredients method of preparation and density of the fruit
pulp Jam and jelly are two different types of fruit preserves (Fruit
preserves are fruits or vegetables that have been prepared and
canned for long term storage)
and the difference between jam and jelly is actually quite significant
in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the
contents Jam is made from whole fruit (fruit pulp) meaning every edible
part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more
evenly-textured spread Because jam includes whole fruit it tends to have more of the
vitamins and minerals found in the parent fruit and it is also usually
only made with one type of fruit whereas jellies may involve a blend
of juices There is also a difference between jam and jelly in terms of
preparation methods
Jam is made by cooking fruit with sugar and water until the fruit
starts to soften and break up releasing its natural pectin Pectin is the
substance which makes jam firm up into a gelatinous solid Once the
fruit is softened the jam can be canned and sealed with some cooks
processing their jam to make the texture more uniform
Jelly can be made with fruit juice or with liquid leftover from
making jam Because whole fruit is not involved pectin must be
added to jelly to ensure that it firms Unlike jelly jam does not need
added pectin illustrating a major difference between jam and jelly
Today the general definition for marmalade is a sweet jelly in
which pieces of fruit and rind are suspended The key is the rind
which gives lends a bitterness to delightfully balance the sweetness
of the jelly Most marmalades have a citrus base either orange
(preferably Seville orange) lime lemon grapefruit or kumquat
FRUIT AND ITS PREPARATION
Important considerations in jam making
Type or variety of fruit
Conditions of the fruit
Suitability for transport and in preparation
Pectin content
High pectin fruits are apples crab apples quinces red currants
gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots
cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-
pectin fruits or with a commercial pectin When a commercial pectin is
added fully ripe fruit can be used The use of this added pectin also
increases the yield from a recipe
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Sweet spreads (The term sweet spreads covers a wide variety of
products in which the main ingredients are sugar and fruit)
ndashbutters jellies jams conserves marmalades and preservesndashadd zest
to meals They can be made from fruit that is not completely suitable for
canning or freezing All contain the four essential ingredients needed to make a jellied
fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of
different ingredients method of preparation and density of the fruit
pulp Jam and jelly are two different types of fruit preserves (Fruit
preserves are fruits or vegetables that have been prepared and
canned for long term storage)
and the difference between jam and jelly is actually quite significant
in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the
contents Jam is made from whole fruit (fruit pulp) meaning every edible
part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more
evenly-textured spread Because jam includes whole fruit it tends to have more of the
vitamins and minerals found in the parent fruit and it is also usually
only made with one type of fruit whereas jellies may involve a blend
of juices There is also a difference between jam and jelly in terms of
preparation methods
Jam is made by cooking fruit with sugar and water until the fruit
starts to soften and break up releasing its natural pectin Pectin is the
substance which makes jam firm up into a gelatinous solid Once the
fruit is softened the jam can be canned and sealed with some cooks
processing their jam to make the texture more uniform
Jelly can be made with fruit juice or with liquid leftover from
making jam Because whole fruit is not involved pectin must be
added to jelly to ensure that it firms Unlike jelly jam does not need
added pectin illustrating a major difference between jam and jelly
Today the general definition for marmalade is a sweet jelly in
which pieces of fruit and rind are suspended The key is the rind
which gives lends a bitterness to delightfully balance the sweetness
of the jelly Most marmalades have a citrus base either orange
(preferably Seville orange) lime lemon grapefruit or kumquat
FRUIT AND ITS PREPARATION
Important considerations in jam making
Type or variety of fruit
Conditions of the fruit
Suitability for transport and in preparation
Pectin content
High pectin fruits are apples crab apples quinces red currants
gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots
cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-
pectin fruits or with a commercial pectin When a commercial pectin is
added fully ripe fruit can be used The use of this added pectin also
increases the yield from a recipe
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
and the difference between jam and jelly is actually quite significant
in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the
contents Jam is made from whole fruit (fruit pulp) meaning every edible
part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more
evenly-textured spread Because jam includes whole fruit it tends to have more of the
vitamins and minerals found in the parent fruit and it is also usually
only made with one type of fruit whereas jellies may involve a blend
of juices There is also a difference between jam and jelly in terms of
preparation methods
Jam is made by cooking fruit with sugar and water until the fruit
starts to soften and break up releasing its natural pectin Pectin is the
substance which makes jam firm up into a gelatinous solid Once the
fruit is softened the jam can be canned and sealed with some cooks
processing their jam to make the texture more uniform
Jelly can be made with fruit juice or with liquid leftover from
making jam Because whole fruit is not involved pectin must be
added to jelly to ensure that it firms Unlike jelly jam does not need
added pectin illustrating a major difference between jam and jelly
Today the general definition for marmalade is a sweet jelly in
which pieces of fruit and rind are suspended The key is the rind
which gives lends a bitterness to delightfully balance the sweetness
of the jelly Most marmalades have a citrus base either orange
(preferably Seville orange) lime lemon grapefruit or kumquat
FRUIT AND ITS PREPARATION
Important considerations in jam making
Type or variety of fruit
Conditions of the fruit
Suitability for transport and in preparation
Pectin content
High pectin fruits are apples crab apples quinces red currants
gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots
cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-
pectin fruits or with a commercial pectin When a commercial pectin is
added fully ripe fruit can be used The use of this added pectin also
increases the yield from a recipe
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Jam is made by cooking fruit with sugar and water until the fruit
starts to soften and break up releasing its natural pectin Pectin is the
substance which makes jam firm up into a gelatinous solid Once the
fruit is softened the jam can be canned and sealed with some cooks
processing their jam to make the texture more uniform
Jelly can be made with fruit juice or with liquid leftover from
making jam Because whole fruit is not involved pectin must be
added to jelly to ensure that it firms Unlike jelly jam does not need
added pectin illustrating a major difference between jam and jelly
Today the general definition for marmalade is a sweet jelly in
which pieces of fruit and rind are suspended The key is the rind
which gives lends a bitterness to delightfully balance the sweetness
of the jelly Most marmalades have a citrus base either orange
(preferably Seville orange) lime lemon grapefruit or kumquat
FRUIT AND ITS PREPARATION
Important considerations in jam making
Type or variety of fruit
Conditions of the fruit
Suitability for transport and in preparation
Pectin content
High pectin fruits are apples crab apples quinces red currants
gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots
cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-
pectin fruits or with a commercial pectin When a commercial pectin is
added fully ripe fruit can be used The use of this added pectin also
increases the yield from a recipe
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
FRUIT AND ITS PREPARATION
Important considerations in jam making
Type or variety of fruit
Conditions of the fruit
Suitability for transport and in preparation
Pectin content
High pectin fruits are apples crab apples quinces red currants
gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots
cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-
pectin fruits or with a commercial pectin When a commercial pectin is
added fully ripe fruit can be used The use of this added pectin also
increases the yield from a recipe
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Strawberries
Strawberries are of better quality in England than in any other country
in the world and are in great demand for jam making
Strawberries are easily bruised and then the juice rapidly drains away
involving heavy losses in weight and flavor For this reason they should
be picked just before they are fully ripe
One of the major problems in handling strawberries is the removal of
the stalk and plug This is an operation which can only be done by hand
and is usually performed by women sometimes on a site near the field
but usually in the jam factory
Plugged strawberries should be processed immediately as they
quickly deteriorate
Any dirt or grit should also be removed and this can be done by
spraying with water
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Where it is found necessary to transport strawberries over long
distances from the large growing areas to the big towns it is an
advantage to keep the fruit as cool as possible If packed in totally
enclosed trucks or wagons blocks of solidified carbon dioxide can be
used to reduce and maintain the temperature at about 400F for the
period of the journey
Raspberries
Raspberries are almost as popular as strawberries because of their
attractive flavor
Varieties Lloyd George and Norfolk Giant
They should be picked carefully without plugs when they are fully
ripe and converted to jam as quickly as possible
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Raspberries Blackcurrants
Gooseberries
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Sometimes raspberries will develop mould growth within a few hours
if they are moist and the weather is warm
Solid carbon dioxide can be use if fruits are in good condition and it
is necessary to store or transport overnight
For transport purposes casks are preferable to baskets as they prevent
wastage of juice
Blackcurrants
Fine flavor and high nutritional value
Most varieties of blackcurrants are suitable for jam making but the
best is probably ldquoBaldwinrdquo
The fruit usually arrives at the factory on stalks which can either be
removed by hand using a table fork to free the berries or by a strigging
machine
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Gooseberries
Gooseberries can produce a very excellent jam but there is only a
small demand for this preserve
The most important consideration for jam-making is the stage of
ripeness and they should always be picked when pale green
Ripe gooseberries lack the delicate flavor of the greener fruit They
produce a muddy colored jam and the skins are tough
Before cooking the tops and tails must be removed (snibbing
machine)
Water sprays help to remove the waste material and also to wash the
fruit
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Plums
Plums are very suitable for jam making as they contain both pectin and
acid in plenty
Size of plums plays an important part in their economic use since it is
better to use a large plum with a small stone than a small plum with a
large stone
Apples
Apples are never used alone in jam but they are very often a component
of mixtures of fruit
The green and hard type of apples are suitable not the soft kinds or
those with pink flesh
Citrus fruit
Citrus fruits are used for making marmalade
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
PRESERVATION OF FRUIT
Jam made from fresh fruit commands a higher price than that made
from preserved pulp
Very few factories are equipped to make all the fruit arriving during
the very short harvesting season into finished jam Even if it were
possible it is unlikely to be desirable to store such a large quantity of
finished goods
By preserving the fruit employment can be maintained throughout
the year
In times of glut when fruit is cheap enough pulp can be made to
ensure against a bad harvest
The commonest method of preserving jam fruit in Britain is by the
use of sulphurous acid but freezing or canning is used extensively in
USA
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
SO2 in the form of per cent solution in water is used as preservative
The main advantage of using sulfurous acid (for simplicity in the text
SO2 is used instead of sulfurous acid) as a chemical preservative is that
the bulk of it is driven off in the boiling process
Legal regulations require that there shall be not more than 40 ppm of
SO2 in the finished jam
In Great Britain SO2 is the only preservative used or permitted
The United States permits the use of SO2 or sodium benzoate if
declared
Australia New Zealand and many continental countries prohibit the
use of any preservative
Citrus fruits plums and blackcurrants are not seriously affected by
storage in SO2 but strawberries and raspberries lose their flavour and
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
sometimes completely disintegrate
Fruit can be preserved with SO2 either in the raw or cooked state
Strawberries raspberries and blackberries are best treated without
cooking whereas those with skins such as plums gooseberries black
and red currants are usually cooked before preserving as the storage in
SO2 tends to toughen the uncooked skins
The most convenient container for storage is the 40-gallon cask
Other methods such as glass containers or large concrete tanks are
used
If the fruit is to be preserved in the uncooked state it should be
carefully cleaned and prepared For every hundredweight of
strawberries to be placed in a cask frac12 gallon of fresh water is first put
into the unheaded container
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
The fruit is then added and then a final frac12 gallon of water per cwt is
poured in on top of the fruit This procedure helps to mix the fruit and
water as it is not possible to stir them up at all without breaking the
berries Raspberries and blackberries do not require any water When
the cask is full it can be headed up and placed on the roll Three pints of
6 per cent SO2 solution per cwt of fruit are then poured in through the
bunghole and the cask rolledPreparation of cooked fruit pulp
Cooking is the important step for the preparation of pulp
The cooking process in which the fruit is steamed for 10 to 20
mins should aim at bursting the skins but it should not be allowed to
break up the fruit into a mash destroying all the color and flavor
The cooking process should also serve to preserve the pectin
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
The old-fashioned method was to use steaming barrels but these
have been largely replaced by stainless steel pulping vats Near the
bottom of the vat is fitted a single coil of steam pipe which is
perforated every six inches to allow the steam to pass into the fruit
The amount of fruit and water must be carefully controlled and
also the weight of the finished batch so that the percentage of fruit in
the finished pulp is known when it is used for jam making
The cooked pulp is passed through the sieving machine and
collected in the receiving tank (Barrels can be filled from the tank as
required)
Hot pulp (those with skins such as plums gooseberries black and
red currants) are allowed to cool when 3 pints of SO2 solution are
added for each 1 cwt of pulp
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
JAM BOILING
The boiling of jam can be carried out either in
1) Small open pans
40 gallon capacity
Produces the higher quality jam
Common in Great Britain
Requires considerable skill and experience
2) or Large vacuum pans
A ton per charge
Used in USA
Emphasis on a high rate of production
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
Boiling is one of the most important steps in the jelly making
process as it dissolves the sugar and causes union of sugar acid and
pectin to form a jelly
It usually causes a coagulation of certain organic compounds that
can be skimmed from the surface during boiling and their removal
renders the jelly clearer
The principal purpose of boiling is to increase the concentration of
sugar to the point where jelling occurs
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
The sugar and water (about 1 gallon) are placed in the boiling pan
and heated together to dissolve the sugar
In some plants sugar syrup is made in a separate plant filtered
and pumped to the boiling pans
The fruit pulp and pectin are then added and the mixture
vigorously boiled until the temperature reached 2200F Boiling time
should be as short as possible and should never exceed ten minutes
Five to seven minutes is the optimum time Prolonged boiling
reduces the setting power of the pectin and yields dull-looking
caramelized jam with poor flavor It also creates an excessive
amount of invert sugar from which dextrose may crystallise out
The solids are then checked on the refractometer and as soon as
they reach 685 per cent the steam is turned off
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
It is essential in order to produce a jam of good quality and with
satisfactory keeping properties to boil to a soluble solids content 65
to 70 percent 685 per cent serves as a good end point for the jam
Where vacuum pans are used sugar water and pectin are heated
together to about 1400F in open pans The fruit is then added and
several batches of this mixture are transferred by suction to a large
vacuum pan where boiling is finished under a vacuum of 25 to 28
inches at a final temperature of 1400F
The ldquosettingrdquo of the jam is controlled by the pH of the boil All
ingredients fruit pulp sugar pectin and water affect the pH and
further adjustment can be made by the addition of citric acid either at
the beginning or the end of the boil A good gel is only obtained
when the pH lies between 30 and 32
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
The presence of acid both in the fruit and added separately causes
inversion of the sucrose in which one molecule of sucrose is converted
into one molecule of dextrose and one molecule of levulose which
constitutes invert sugar Invert sugar discourages the sugar
crystallization in the jelly
C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6
(dextrose)
The degree of inversion must be controlled to give a final invert sugar
content between 25 and 40 per cent If less than 25 per cent cane sugar
will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo
may be weak
Inversion of sugar is greatly affected by temperature It is therefore
important in the control of this factor that the jam should be cooled as
quickly as possible after boiling
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
-
FINISHING AND STORING
The jam as it comes from the boiling pans will be at a temperature of
over 2120F and it must be cooled to 185oF to 190oF
This can be accomplished in tanks with double walls through which
cold water is flowing or in a revolving cylinder surrounded by a water
jacket
Filling
The cooled jam can be filled into containers either by hand or
machine
Hand filling is slow but is preferable where only small lots are being
made or large containers such as 28 Ib tins are required
Hand filling also avoids the breaking up of whole fruit which might
occur in a machine
The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
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The usual method of hand filling is on circular rotating tables The
jam is brought to the tables in bogies and poured into the jars which
are arranged around the edge of the table by means of a dipper
which has a funnel shaped end
After filling the operator makes the table rotate so that the filled
jars pass round to another worker
A disc of tissue is then laid flat on the surface The presence of the
disc of tissue is intended to prevent the condensation of moisture on
the surface of the jam This condensation would create localized
areas of low concentration in which mould would readily grow
For high rate of production a filling machine is indispensable
The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
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The jam is fed from the cooler into a sump from which it is drawn
by means of a double acting plunger-type pump which in turn
delivers it in fixed amounts to the filling nozzle of rotating head The
exact amount delivered can be adjusted by means of a hand wheel
which regulates the length of the stroke of the pump
- Pectin Substances-Plant Gums
- Slide 2
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