Chemistry Project - Analysis of the Different Samples of Milk for Presence of Casein

ChemistryProjectAnalysisofthedifferentsamplesofmilkforpresenceofCaseinFriday,6December2013

Milk is the best and cheapest source of nutrition and anarticle of daily diet, easily accepted and used by all the age

groups in rural as well as in urban areas. It provide appreciableamount of fats and protein and also provides body building

vitamins along with furnishing energy giving lactose and manyother nutrients, therefore an ideal food for pregnant femaleand infants. Milk can provide a wide range of readily availablenutrients to maintain health and normal growth of body. Milk

has no pronounced taste what is slightly sweet to mostpersons. Milk is the largest and the single most important

commodity within the livestock sector. Although slightly variesin composition and properties, the milk of different speciescontain the same constituents in general. On average, milk is

made up of 87.4% water and 12.6% milk solids (3.7% fat, 8.9%milk solids-not-fat). The milk solids-not-fat contain protein(3.4%), lactose (4.8%), and minerals (0.7%).Milk fat often

called butter fat is commercially, the most valuableconstituent of milk. It is also of great importance from the

standpoint of the food value of the milk. The agreeableflavour of rich milk and to a large extent of other dairy

products is largely due to the milk fat. Proteins are among themost complex of organic substances. They contain carbon,

hydrogen, oxygen, nitrogen, sulphur and sometimesphosphorus. The protein of milk is not a single compound butincludes two major proteins and small quantities of others.

Between them casein constitute about 80 % of the total andlacto albumin 18%. A third protein recognized as present in

ABSTRACTOFREPORT

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milk is lacto globulin. It is present in very small amounts,probably about 0.05 to 0.07 %. Ash constituents of milk areextremely important in their relation to the heat stability of

the milk.

A File Report submitted to :

____________________________ Internal Examiner

_____________________________Head Of Chemistry Department Principal

This is to certify that this dissertation titled

Analysis of different samples of milk for presenceof Casein was submitted by Patit Pawan

Barikto

ANALYSISOFDIFFERENTSAMPLESOFMILKFORPRESENCEOFCASEIN

CERTIFICATE

Head of Chemistry Department of

Kendriya Vidyalaya, Chittaranjan, W.B.

carried under guidance and supervision duringthe

Academic year 2013-2014.

I wish to express my deep gratitude andsincere thanks to thePrincipal,KendriyaVidyalaya, Chittaranjan, W.B. for his

encouragement and for all the facilities thathe provided for this project work. I sincerelyappreciate this magnanimity by taking me intohis fold for which I shall remain indebted to

him. I extend my hearty thanks toMr.K.Batabyal (PGT Chemistry), who guided me tothe successful completion of this project. Itake this opportunity to express my deep

sense of gratitude for his invaluable guidance,constant encouragement, constructive

comments, sympathetic attitude and immensemotivation, which has sustained my efforts at

all stages of this project work.

ACKNOWLEDGEMENT

I do hereby declare that this project work hasbeen

originally carried under the guidance andsupervision

of

Mr. K. Batabyal (PGT Chemistry),

Head of Chemistry Department,


Patit Pawan BarikXII ARoll no.- 32

Introduction

DECLARATION

TABLEOFCONTENTS

Aim

Requirement

Theory

Procedure

Observations

Conclusion

Reference

Milk is a food of exceptional interest. Not only is milk anexcellent food for the very young, but humans have also

adapted milk, specifically cows milk, as a food substance for

INTRODUCTION

adapted milk, specifically cows milk, as a food substance forpersons of all ages. Many specialised milk products like

cheese, curd, butter and ice cream are staples of our diet.Milk is probably the most nutritionally-complete food thatcan be found in nature. This property is important for milk,

since it is the only food young mammals consume in thenutritionally significant weeks following birth.

Whole milk contains Vitamins (principally Thiamine,Riboflavin, Pantothenic acid, and Vitamins A, D, and K),

Minerals (Calcium, Potassium, Sodium, Phosphorus, and tracemetals), proteins (which include all the essential amino

acids), carbohydrates (chiefly Lactose), and Lipids (fats).The only important elements in which milk is seriously

deficient are iron and Vitamin C. Infants are usually bornwith a storage supply of iron large enough to meet their

needs for several weeks. Vitamin-C is easily secured throughan orange juice supplement. Milk is the largest and the single

most important commodity within the livestock sector.Although slightly varies in composition and properties, themilk of different species contain the same constituents ingeneral. On average, milk is made up of 87.4% water and

12.6% milk solids (3.7% fat, 8.9% milk solids-not-fat). Themilk solids-not-fat contain protein (3.4%), lactose (4.8%),and minerals (0.7%).Milk fat often called butter fat iscommercially, the most valuable constituent of milk. It isalso of great importance from the standpoint of the food

value of the milk. The agreeable flavour of rich milk and to alarge extent of other dairy products is largely due to themilk fat. Proteins are among the most complex of organic

substances. They contain carbon, hydrogen, oxygen,nitrogen, sulphur and sometimes phosphorus. The protein ofmilk is not a single compound but includes two major proteins

and small quantities of others. Between them caseinconstitute about 80 % of the total and lacto albumin 18%. Athird protein recognized as present in milk is lacto globulin.It is present in very small amounts, probably about 0.05 to

0.07 %. Ash constituents of milk are extremely important intheir relation to the heat stability of the milk.

PreviousExperimentalObservations&

OBSERVATIONSAverage Percentage Composition of Milk from VariousMammals:

Source of milk Water(%) Minerals(%) Proteins(%) Fats(%) Carbohydrates

(%)

Cow 87.1 0.7 3.4 3.9 4.9

Human 87.4 0.2 1.4 4.0 4.9

Goat 87.0 0.7 3.3 4.2 4.8

Sheep 82.6 0.9 5.5 6.5 4.5

RESULTSThe Buffalos milk has highest casein presence in all

the samples of milk. Therefore, buffalos milk is mostsuitable for nutrition.

Casein is a phosphoprotein, which has phosphate groups areattached to some of the amino acid side chains. Casein

exists in milk as the calcium salt, calcium caseinate. This salthas a complex structure. It is composed of , , and

caseins which form a micelle, or a solubilized unit. Neitherthe nor the casein is soluble in milk, singly or in

combination. If casein is added to either one, or to acombination of the two, however, the result is a caseincomplex that is soluble owing to the formation of the

micelle. The casein is thought to stabilize the micelle.Since both and casein are phosphoproteins, they are

precipitated by calcium ions.

The casein protein, however, has fewer phosphate groupsand a high content of carbohydrate bound to it. It is also

thought to have all its serine and threonine residues (whichhave hydroxyl groups), as well as its bound carbohydrates,

Results

CASEIN

on only one side of its outer surfaces. This portion of itsouter surface is easily solubilized in water since these polargroups are present. The other portion of its surface bindswell to the water-insoluble and caseins and solubilizes

them by forming a protective colloid or micelle around them.Since the entire outer surface of the micelle can be

solubilized in water, the unit is solubilized as a whole, thusbringing the and caseins, as well as casein, into

solution. Calcium caseinate has its isoelectric (neutrality)point at pH 4.6. Therefore, it is insoluble in solutions of pHless than 4.6. The pH of milk is about 6.6 therefore caseinhas a negative charge at this pH and is solubilized as a salt.If acid is added to milk, the negative charges on the outer

surface of the micelle are neutralized (the phosphategroups are protonated) and the neutral protein precipitates:

Ca2+Caseinate + 2 HCl Casein + CaCl2

The calcium ions remain in solution. When milk sours, lacticacid is produced by bacterial action and the consequent

lowering of the pH causes the same clotting reaction. Theisolation of casein from milk will be carried out in this

experiment.The casein in milk can also be clotted by the action of an

enzyme called rennin. Rennin is found in the fourth stomachof young calves. However, both the nature of the clot andthe mechanism of clotting differ when rennin is used. Theclot formed using rennin, calcium paracaseinate, contains

calcium.

Ca2+Caseinate + Rennin Ca2+Paracaseinate + A SmallPeptide

Rennin is a hydrolytic enzyme (peptidase) and actsspecifically to cleave peptide bonds between phenylalanineand methionine residues. It attacks the casein, breaking

the peptide chain so as to release a small segment of it. Thisdestroys the water-solubilizing surface of the casein,which protects the inner and caseins and causes the

entire micelle to precipitate as calcium paracaseinate. Milkcan be decalcified by treatment with oxalate ion, whichforms an insoluble calcium salt. If the calcium ions are

removed from milk, a clot will not be formed when the milkis treated with rennin.

The clot, or curd, formed by the action of rennin is soldcommercially as cottage cheese. The liquid remaining iscalled the whey. The curd can also be used in producing

various types of cheese. It is washed, pressed to remove anyexcess whey, and chopped. After this treatment, it ismelted, hardened and ground. The ground curd is thensalted, pressed into molds, and set aside to age .It is a

major protein constituent in milk & is a mixed phosphor-protein. Casein has isoelectric pH of about 4.7 and can be

easily separated around this isoelectric pH. It readilydissolves in dilute acids and alkalies. Casein is present in milk

as Calcium Caseinate in the form of micelles. Thesemicelles have negative charge and on adding acid to milk the

negative charges are neutralized.Natural milk is an opaque white fluidsecreted by the

mammary glands of female mammal. The main constituentsof natural milk are Protein, Carbohydrate, Minerals,

Vitamins, Fats and Water and are a complete balanced diet.Fresh milk is sweetish in taste. However, when it is kept forlong time at a temperature of 5 it become sour because ofbacteria present in air. These bacteria convert lactose of

milk into lactic acid which is sour in taste. In acidicconditioncasein of milk starts separating out as a precipitate. Whenthe acidity in milk is sufficient and temperature is around

36, it forms semi-solid mass, called curd.

To study the quantity of Casein in different samplesof milk.

Beakers (250 ml)

Filter-paper

Glass rod

Weight box

Filtration flask

AIM

REQUIREMENTS

Filtration flask

Buchner funnel

Test tubes

Porcelain dish

Different samples of milk

1 % Acetic acid solution

Ammonium sulphate solution

Ca2+Caseinate2- + 2 CH3COOH(aq) Casein +(CH3COO)2Ca

Casein is a phosphoprotein, which has phosphate groups areattached to some of the amino acid side chains.

These are attached mainly to the hydroxyl groups of theserine and threonine moieties. Actually, casein is a mixtureof at least three similar proteins, which differ primarily inmolecular weight and amount of phosphorus they contain

(number of phosphate groups). Casein exists in milk as thecalcium salt, calcium caseinate. This salt has a complex

structure. It is composed of , , and caseins which form amicelle, or a solubilized unit. Neither the nor the casein

is soluble in milk, singly or in combination. If casein isadded to either one, or to a combination of the two,

however, the result is a casein complex that is soluble owingto the formation of the micelle. The casein is thought to

stabilize the micelle. Since both and casein arephosphoproteins, they are precipitated by Calcium ions.



CHEMICALREACTION

THEORY











calcium.











negative charges are neutralized.

1. A clean dry beaker has been taken, followed byputting 20 ml of cows milk into it and adding 20 ml ofsaturated ammonium sulphate solution slowly and withstirring. Fat along with Casein was precipitate out.

2. The solution was filtered and transferred theprecipitates in another beaker. Added about 30 ml ofwater to the precipitate. Only Casein dissolves in waterforming milky solution leaving fat undissolved.

3. The milky solution was heated to about 40oC and add1% acetic acid solution drop-wise, when casein gotprecipitated.

4. Filtered the precipitate, washed with water and theprecipitate was allowed to dry.

5. Weighed the dry solid mass in a previously weighedwatch glass.

6. The experiment was repeated with other samples ofmilk.

PROCEDURE

According to above experiment :

Sl. No. Source of Milk Weight of Dried Solid Mass

The __________ milk has highest value of the dried solidmass i.e. the composition of Casein is highest in the sample

of ________ milk.

The ________ milk has the highest presence of casein inmilk. Therefore, ________ milk is the best for nutrition.

Wikipedia

Encyclopedia Encarta Britannica

icbse.nic.in

Practical Chemistry books

OBSERVATIONS

CONCLUSION

SOLUTIONTOTHEANALYSIS

REFERENCES

Readmore

PostedbyPatitPawanBarikat18:46 Nocomments:

This is the project created by me in Class 12th forthe external practical exam.

Recommend this on Google

Milk is the best and cheapest source of nutrition and anarticle of daily diet, easily accepted and used by all the age

groups in rural as well as in urban areas. It provide appreciableamount of fats and protein and also provides body building

vitamins along with furnishing energy giving lactose and manyother nutrients, therefore an ideal food for pregnant femaleand infants. Milk can provide a wide range of readily availablenutrients to maintain health and normal growth of body. Milk

has no pronounced taste what is slightly sweet to mostpersons. Milk is the largest and the single most important

commodity within the livestock sector. Although slightly variesin composition and properties, the milk of different speciescontain the same constituents in general. On average, milk is

made up of 87.4% water and 12.6% milk solids (3.7% fat, 8.9%milk solids-not-fat). The milk solids-not-fat contain protein(3.4%), lactose (4.8%), and minerals (0.7%).Milk fat often

called butter fat is commercially, the most valuableconstituent of milk. It is also of great importance from the

standpoint of the food value of the milk. The agreeableflavour of rich milk and to a large extent of other dairy

products is largely due to the milk fat. Proteins are among themost complex of organic substances. They contain carbon,

hydrogen, oxygen, nitrogen, sulphur and sometimesphosphorus. The protein of milk is not a single compound but

ABSTRACTOFREPORT

includes two major proteins and small quantities of others.Between them casein constitute about 80 % of the total andlacto albumin 18%. A third protein recognized as present in

milk is lacto globulin. It is present in very small amounts,probably about 0.05 to 0.07 %. Ash constituents of milk areextremely important in their relation to the heat stability of

the milk.

A File Report submitted to :

____________________________ Internal Examiner

_____________________________Head Of Chemistry Department Principal

This is to certify that this dissertation titled

Analysis of different samples of milk for presenceof Casein was submitted by Patit Pawan

ANALYSISOFDIFFERENTSAMPLESOFMILKFORPRESENCEOFCASEIN

CERTIFICATE

Barikto

Head of Chemistry Department of


carried under guidance and supervision duringthe

Academic year 2013-2014.

I wish to express my deep gratitude andsincere thanks to thePrincipal,KendriyaVidyalaya, Chittaranjan, W.B. for his

encouragement and for all the facilities thathe provided for this project work. I sincerelyappreciate this magnanimity by taking me intohis fold for which I shall remain indebted to

him. I extend my hearty thanks toMr.K.Batabyal (PGT Chemistry), who guided me tothe successful completion of this project. Itake this opportunity to express my deep

sense of gratitude for his invaluable guidance,constant encouragement, constructive

comments, sympathetic attitude and immensemotivation, which has sustained my efforts at

all stages of this project work.

ACKNOWLEDGEMENT

I do hereby declare that this project work hasbeen

originally carried under the guidance andsupervision

of

Mr. K. Batabyal (PGT Chemistry),

Head of Chemistry Department,


Patit Pawan BarikXII ARoll no.- 32

Introduction

DECLARATION

TABLEOFCONTENTS

Aim

Requirement

Theory

Procedure

Observations

Conclusion

Reference

Milk is a food of exceptional interest. Not only is milk anexcellent food for the very young, but humans have also

adapted milk, specifically cows milk, as a food substance for

INTRODUCTION

adapted milk, specifically cows milk, as a food substance forpersons of all ages. Many specialised milk products like

cheese, curd, butter and ice cream are staples of our diet.Milk is probably the most nutritionally-complete food thatcan be found in nature. This property is important for milk,

since it is the only food young mammals consume in thenutritionally significant weeks following birth.

Whole milk contains Vitamins (principally Thiamine,Riboflavin, Pantothenic acid, and Vitamins A, D, and K),

Minerals (Calcium, Potassium, Sodium, Phosphorus, and tracemetals), proteins (which include all the essential amino

acids), carbohydrates (chiefly Lactose), and Lipids (fats).The only important elements in which milk is seriously

deficient are iron and Vitamin C. Infants are usually bornwith a storage supply of iron large enough to meet their

needs for several weeks. Vitamin-C is easily secured throughan orange juice supplement. Milk is the largest and the single

most important commodity within the livestock sector.Although slightly varies in composition and properties, themilk of different species contain the same constituents ingeneral. On average, milk is made up of 87.4% water and

12.6% milk solids (3.7% fat, 8.9% milk solids-not-fat). Themilk solids-not-fat contain protein (3.4%), lactose (4.8%),and minerals (0.7%).Milk fat often called butter fat iscommercially, the most valuable constituent of milk. It isalso of great importance from the standpoint of the food

value of the milk. The agreeable flavour of rich milk and to alarge extent of other dairy products is largely due to themilk fat. Proteins are among the most complex of organic

substances. They contain carbon, hydrogen, oxygen,nitrogen, sulphur and sometimes phosphorus. The protein ofmilk is not a single compound but includes two major proteins

and small quantities of others. Between them caseinconstitute about 80 % of the total and lacto albumin 18%. Athird protein recognized as present in milk is lacto globulin.It is present in very small amounts, probably about 0.05 to

0.07 %. Ash constituents of milk are extremely important intheir relation to the heat stability of the milk.

PreviousExperimentalObservations&

OBSERVATIONSAverage Percentage Composition of Milk from VariousMammals:

Source of milk Water(%) Minerals(%) Proteins(%) Fats(%) Carbohydrates

(%)

Cow 87.1 0.7 3.4 3.9 4.9

Human 87.4 0.2 1.4 4.0 4.9

Goat 87.0 0.7 3.3 4.2 4.8

Sheep 82.6 0.9 5.5 6.5 4.5

RESULTSThe Buffalos milk has highest casein presence in all

the samples of milk. Therefore, buffalos milk is mostsuitable for nutrition.

Casein is a phosphoprotein, which has phosphate groups areattached to some of the amino acid side chains. Casein

exists in milk as the calcium salt, calcium caseinate. This salthas a complex structure. It is composed of , , and

caseins which form a micelle, or a solubilized unit. Neitherthe nor the casein is soluble in milk, singly or in

combination. If casein is added to either one, or to acombination of the two, however, the result is a caseincomplex that is soluble owing to the formation of the

micelle. The casein is thought to stabilize the micelle.Since both and casein are phosphoproteins, they are

precipitated by calcium ions.



Results

CASEIN











calcium.











negative charges are neutralized.Natural milk is an opaque white fluidsecreted by the

mammary glands of female mammal. The main constituentsof natural milk are Protein, Carbohydrate, Minerals,

Vitamins, Fats and Water and are a complete balanced diet.Fresh milk is sweetish in taste. However, when it is kept forlong time at a temperature of 5 it become sour because ofbacteria present in air. These bacteria convert lactose of

milk into lactic acid which is sour in taste. In acidicconditioncasein of milk starts separating out as a precipitate. Whenthe acidity in milk is sufficient and temperature is around

36, it forms semi-solid mass, called curd.

To study the quantity of Casein in different samplesof milk.

Beakers (250 ml)

Filter-paper

Glass rod

Weight box

Filtration flask

AIM

REQUIREMENTS

Filtration flask

Buchner funnel

Test tubes

Porcelain dish

Different samples of milk

1 % Acetic acid solution

Ammonium sulphate solution

Ca2+Caseinate2- + 2 CH3COOH(aq) Casein +(CH3COO)2Ca

Casein is a phosphoprotein, which has phosphate groups areattached to some of the amino acid side chains.

These are attached mainly to the hydroxyl groups of theserine and threonine moieties. Actually, casein is a mixtureof at least three similar proteins, which differ primarily inmolecular weight and amount of phosphorus they contain

(number of phosphate groups). Casein exists in milk as thecalcium salt, calcium caseinate. This salt has a complex

structure. It is composed of , , and caseins which form amicelle, or a solubilized unit. Neither the nor the casein

is soluble in milk, singly or in combination. If casein isadded to either one, or to a combination of the two,

however, the result is a casein complex that is soluble owingto the formation of the micelle. The casein is thought to

stabilize the micelle. Since both and casein arephosphoproteins, they are precipitated by Calcium ions.



CHEMICALREACTION

THEORY











calcium.











negative charges are neutralized.

1. A clean dry beaker has been taken, followed byputting 20 ml of cows milk into it and adding 20 ml ofsaturated ammonium sulphate solution slowly and withstirring. Fat along with Casein was precipitate out.

2. The solution was filtered and transferred theprecipitates in another beaker. Added about 30 ml ofwater to the precipitate. Only Casein dissolves in waterforming milky solution leaving fat undissolved.

3. The milky solution was heated to about 40oC and add1% acetic acid solution drop-wise, when casein gotprecipitated.

4. Filtered the precipitate, washed with water and theprecipitate was allowed to dry.

5. Weighed the dry solid mass in a previously weighedwatch glass.

6. The experiment was repeated with other samples ofmilk.

PROCEDURE

According to above experiment :

Sl. No. Source of Milk Weight of Dried Solid Mass

The __________ milk has highest value of the dried solidmass i.e. the composition of Casein is highest in the sample

of ________ milk.

The ________ milk has the highest presence of casein inmilk. Therefore, ________ milk is the best for nutrition.

Wikipedia

Encyclopedia Encarta Britannica

icbse.nic.in

Practical Chemistry books

OBSERVATIONS

CONCLUSION

SOLUTIONTOTHEANALYSIS

REFERENCES

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PostedbyPatitPawanBarikat18:46 Nocomments:

This is the project created by me in Class 12th forthe external practical exam.

Recommend this on Google

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Chemistry Project - Analysis of the Different Samples of Milk for Presence of Casein

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