Post on 12-Nov-2014
CHAPTER 1
INTRODUCTION
Sweet potatoes grow year-round in the tropics. Sweet potato has the shortest
growing cycle of the root crops grown in the tropics. The crop is normally harvested
about 4 months after planting and harvesting may be spread over several months. In a
temperate climate, harvest must take place before risk of frost.
To widen its optimization sweet potato can be processed into flour and starch
which are less bulky and more stable than the very perishable fresh root. Sweet potato
would be in greater demand if it could be used in staple food products which have wide
consumption, such as bread and pasta/ noodle. These which are used as rice substitutes in
the Asia-Pacific region. Increased used of sweet potato would also help offset the
increasing wheat importation of developing countries which constitutes an economic
drain for many economies.
1.1 OBJECTIVES
1.1.1 GENERAL OBJECTIVE
1.1.2.1 To evaluate the optimization of Sweet Potato (Ipomoea Batatas)
Flour in muffin making
1.1.2 SPECIFIC OBJECTIVES
1.1.2.1 To learn the technique and process of muffin making
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1.1.2.2 To evaluate the proximate analysis and microbiological
characteristic of Sweet Potato muffin
1.1.2.3 To evaluate the sensory characteristic of sweet potato muffin
1.1.2.4 To study the shelf life of sweet potato muffin
1.1.2.5 To study the effect of other ingredients such as flour, and fat in
microbiological and sensory characteristic of muffin
1.1.2.6 To study the standard temperature of oven in muffin using sweet
potato flour
1.2 HYPOTHESIS
1.2.1 Null
1.2.1.1 The temperature to be subjected to the bread will not cause nutritional lost
of the product.
1.2.1.2 The process / technique of bread making will not affect the quality of the
product.
1.2.1.3 The proportion of the ingredients will not affect the quality of the product
and its characteristics.
1.2.2 Alternative
1.2.2.1 The temperature to be subjected to the bread will be the cause of
nutritional lost of the product
1.2.2.2 The process technique of bread making will affect the quality of the
product.
1.2.2.3 The proportion of the ingredients will affect the quality of the product and
its characteristics.
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1.3 SIGNIFICANCE OF THE STUDY
Nowadays, consumers are looking for a food that is high in carbohydrates.
Carbohydrate food is the most efficient fuel for energy production that can be use in our
daily activities.
This study wants to produce a new product that can be consumed and
incorporated on carbohydrate intake. Also to produce product that is a good source of
potassium, pyridoxine, a good anti-oxidant. Another idea is to give idea the local
processors to produce commercial product made from sweet potato flour. As a result, it
can expand the use of sweet potato flour especially in baking purposes.
1.4 ASSUMPTION
1.4.1 The Sweet Potato Flour has a different component from the other flour.
1.4.2 The chemical composition of sweet potato flour might be affected when it is
subjected to heat and other process treatment.
1.4.3 The quality of muffin might be affected by adding other ingredients.
1.5 SCOPE AND LIMITATION
1.5.1 Scope
The study of the Sweet Potato Muffin will also cover recent study about the
optimization of sweet potato flour in bread making.
1.5.2 Limitation
It will not include any information that will be related to the topic. It will cover
from the month of July to March 2008.
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1.6 DEFINITION OF TERMS
ANOVA (analysis of variance) is a collection of statistical models, and their associated
procedures, in which the observed variance is partitioned into components due to
different explanatory variables. The initial techniques of the analysis of variance were
developed by the statistician and geneticist R. A. Fisher in the 1920s and 1930s, and is
sometimes known as Fisher's ANOVA or Fisher's analysis of variance, due to the use of
Fisher's F-distribution as part of the test of statistical significance.
Box-Behnken Design is an independent quadratic design that does not contain an
embedded factorial or fractional factorial design.
Color is the visual, perceptual property that corresponds to humans, has categories as red,
yellow, white, etc.
Fat consist of a wide group of compounds that are generally soluble in organic solvents
and largely insoluble in water.
Flavor is the sensory impression of a food or other substance, and is determined mainly
by the chemical senses of taste and smell.
Flour is a fine powder made from cereals or other starchy food sources. Flour is the key
ingredient of bread, which is the staple food in many countries, and therefore the
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availability of adequate supplies of flour has often been a major economic and political
issue. Flour can also be made from legumes and nuts, such as soy, peanuts, almonds, and
other tree nuts. Flour is always based on the presence of starches, which are complex
carbohydrates (aka polysaccharides).
Hedonic Rating Scale - is anchored verbally with nine different categories ranging from
like extremely to dislike extremely.
Molds and Yeast Count – is the enumeration of mesophilic aerobic in a medium for
yeast and molds.
Objective Test – is the physical, microbial and chemical methods used as tools for
evaluation of the quality of the food.
Odor / Aroma - are also called smells, which can refer to both pleasant and unpleasant
odors
pH - is a measure of the acidity or alkalinity of a solution.
Subjective Test – is an evaluation based on individual experiences using the five senses.
Sweet potatoes- are botanically known as “Ipomoea batatas”, are the root of a vine in the
morning glory family and native to the New-World tropics.
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Sweet Potato Flour – is specialty flour that is produced from white sweet potatoes. It is
raw flour, not roasted flour and therefore, does not require cooking before use. Dull white
in color, sweet potato flour is stiff in texture and somewhat sweet tasting. High in fiber,
this flour contains more carbohydrates but less protein than common flour.
Temperature - is a physical property of a system that underlies the common notions of
hot and cold; something that is hotter has the greater temperature.
Texture - the way food feels in a person's mouth
Q. D. A. (Quantitative Descriptive Analysis) – uses parameters for describing physical
properties of food like color, texture, aroma, flavor and general appearance of the food. It
is a way of measuring quality characteristics requiring a number of panelists to evaluate
the product.
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CHAPTER II
REVIEW OF RELATED LITERATURE
2.1 Sweet potato
2.1.1 History
Sweet potatoes, botanically known as “Ipomoea Batatas”, are the root of a vine in
the morning glory family and native to the New-World tropics. It history dates back to
750 BC in Peruvian records. Columbus brought the sweet potato to the New World from
the island of Saint Thomas.
The Tiano word for them was “batatas” which eventually became “patata” in
Spanish, “patae” in French and “potato” in English. At that time, “potato” to the sweet
potato and not the generic white potato as it does in English nowadays.
In fact, according to noted food historian waverly Root, the white potato did not
arrive in the northern regions from South America until the late 17th century, more than a
hundred years later.
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2.1.2 Scientific Classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Solanales
Family: Convulvulaceae (morning glory)
Genus: Ipomoea
Species: I. batatas
Group: Dicotyledon
2.1.3 Appearance , Shape and Variety
The yellow or orange tubers are elongated with ends that taper to a point and are
of two dominant types. The paler-skinned sweet potato has a thin, light yellow skin with
pale yellow flesh which is no sweet and has a dry, crumbly texture similar to a white
baking potato. The darker-skinned one (most often called yam in error) has a thicker,
dark orange skin with vivid orange, sweet flesh and moist texture. Varieties include
Goldrush, Georgia Red, Centennial, Puerto Rico, New Jersey and Velvet.
2.1.4 Nutritional Highlights
2.1.4.1 Sweet potatoes are a good source of potassium
Sweet potato and yam health information includes carotene. More times the
recommended daily allowance of Vitamin A, as well as loaded with potassium. These
nutrients help protect against heart attack and stroke. The potassium helps maintain fluid
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and electrolyte balance in the body cells, as well as normal heart functions and blood
pressure.
2.1.4.2 Sweet potatoes are a good source of pyridoxine.
Pyridoxine (Vitamin B6) is a micronutrient, water-soluble vitamin
Helps the body use carbohydrates, fats and proteins, and is essential in converting
tryptophan (essential amino acids) to niacin and linoleic acid (fatty acid) to arachidonic
acid (fatty acid in animal fat).
Lack of pyridoxine results in appetite loss, nausea and vomiting; nervous
irritability and convulsions; and dermatitis around the eyes, mouth, nose and behind the
ears.
2.1.4.3 Vitamin C is a good anti-oxidant.
Vitamin C is a good anti-oxidant found in sweet potato. It has been recognized
and accepted by the U.S. Food and Drug Admin., (FDA) as one of the four dietary
antioxidants, the others being vitamin E, beta-carotene and selenium.
A dietary oxidant is a substance in food that significantly decreases the adverse
effects of harmful chemicals like react oxygen and nitrogen species, and other radicals on
normal physiological functions in human. It acts as a scavenger, sweeping these
chemicals away from damage.
Antioxidant vitamins prevents the oxidation of LDC (low-density lipoproteins)
cholesterol thus may reduce platelet adhesion to the arterial wall. Platelet adhesion favors
development of atheoroscleriotic plagues.
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The recommended dietary allowance (RDA), 1989 for Filipinos for vitamin C,
published by the FNRI-DOST, is 30 mg/day for infants; 35 mg/day for 1-3 children; 75 &
70 mg/day for male and female adults respectively.
2.2 Compositions of Raw Sweet Potato, Sweet Potato Flour and Sweet Potato Muffin
2.2.1 Fiber
2.2.1.1 Importance
Fibers resist bulging has long been known due to their importance in
providing regularity of bowel movement. However, it was during the late 19th
century when the noble effects of fibers in the human body got into the limelight.
Dietary fiber, in general, is a loose term denoting the substances in plant
foods that are not digested by the human digestive enzymes. Simply put, it is what
remains from food cyter digestion.
2.2.1.2 Benefits
2.2.1.2.1 Promote and satisfy weight loss;
2.2.1.2.2 Help prevent compaction of the intestinal content which could
abstract the appendix and permit bacteria to invade and infect it;
2.2.1.2.3 Exercise the muscles of the digestive tract to retain their health and
tone, and resist bulging out into pouches (as in the case of
diverticulosis);
2.2.1.2.4 Act as a broom and regulate wave like motions in the intestines
propelling and pushing the food inside the digestive tract; and
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2.2.1.2.5 Bind bile and carry it out of the body to reduce the risk or cancer
2.2.1.3 Two (2) types of dietary fiber
2.2.1.3.1 Soluble Fiber – forms a gel when mixed with liquids, while
insoluble does not.
2.2.1.3.2 Insoluble Fiber – passes through your digestive tract and is largely
intact
Both types of fiber are important in the diet and prove benefits to the digestive
system by helping maintain regularly the bowel movement.
Soluble fiber has some additional benefits to heart health. It has been
scientifically proven to reduce blood cholesterol levels, which may help reduce your risk
of heart disease.
2.2.2 Proteins
Proteins are large organic compounds made of amino acids arranged in a linear
chain and joined together by peptide bonds between the carboxyl and amino groups of
adjacent amino acid residues. The sequence of amino acids in a protein is defined by a
gene and encoded in the genetic code. Although this genetic code specifies 20 "standard"
amino acids, the residues in a protein are often chemically altered in post-translational
modification: either before the protein can function in the cell, or as part of control
mechanisms. Proteins can also work together to achieve a particular function, and they
often associate to form stable complexes.
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2.2.3 Carbohydrates
Carbohydrates (from 'hydrates of carbon') or saccharides (Greek σάκχαρον
meaning "sugar") are simple organic compounds that are aldehydes or ketones with many
hydroxyl groups added, usually one on each carbon atom that is not part of the aldehyde
or ketone functional group. Carbohydrates are the most abundant of the four major
classes of biomolecules, which also include proteins, lipids and nucleic acids. They fill
numerous roles in living things, such as the storage and transport of energy (starch,
glycogen) and structural components (cellulose in plants, chitin in animals). Additionally,
carbohydrates and their derivatives play major roles in the working process of the
immune system, fertilization, pathogenesis, blood clotting, and development.
2.2.4 Vitamin
A vitamin is a nutrient that is an organic compound required in tiny amounts for
essential metabolic reactions in a living organism. The term vitamin does not include
other essential nutrients such as dietary minerals, essential fatty acids, or essential amino
acids, nor does it encompass the large number of other nutrients that promote health but
that are not essential for life.
2.2.5 Calcium
Calcium (pronounced /ˈkælsiəm/) is the chemical element in the periodic table
that has the symbol Ca and atomic number 20. It has an atomic mass of 40.078. Calcium
is a soft grey alkaline earth metal, and is the fifth most abundant element in the Earth's
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crust. It is essential for living organisms, particularly in cell physiology, and is the most
common metal in many animals.
2.2.6 Fats
Fats consist of a wide group of compounds that are generally soluble in organic
solvents and largely insoluble in water. Chemically, fats are generally triesters of glycerol
and fatty acids. Fats may be either solid or liquid at normal room temperature, depending
on their structure and composition. Although the words "oils", "fats" and "lipids" are all
used to refer to fats, "oils" is usually used to refer to fats that are liquids at normal room
temperature, while "fats" is usually used to refer to fats that are solids at normal room
temperature. "Lipids" is used to refer to both liquid and solid fats. The word "oil" is used
for any substance that does not mix with water and has a greasy feel, such as petroleum
(or crude oil) and heating oil, regardless of its chemical structure.
Fats form a category of lipid, and are distinguished from other lipids by their
chemical structure and physical properties. This category of molecules is important for
many forms of life, serving both structural and metabolic functions. They are an
important part of the diet of most heterotrophs (including humans). Fats or lipids are
broken down in the body by enzymes called lipase produced in the pancreas.
Examples of edible animal fats are lard (pig fat), fish oil, and butter or ghee. They
are obtained from fats in the milk, meat and under the skin of the animal. Examples of
edible plant fats are peanut, soya bean, sunflower, sesame, coconut, olive and vegetable
oils. Margarine and vegetable shortening, which can be which derived from the above
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oils, are used mainly for baking. These examples of fats can be categorized into saturated
fats and unsaturated fats.
2.2.7 Riboflavin
Riboflavin (E101), also known as vitamin B2, is an easily absorbed micronutrient
with a key role in maintaining health in animals. It is the central component of the
cofactors FAD and FMN, and is therefore required by all flavoproteins. As such, vitamin
B2 is required for a wide variety of cellular processes. Like the other B vitamins, it plays
a key role in energy metabolism, and is required for the metabolism of fats,
carbohydrates, and proteins.
Milk, cheese, leafy green vegetables, liver, legumes such as mature soybeans [1],
yeast and almonds are good sources of vitamin B2, but exposure to light destroys
riboflavin.
2.2.8 Niacin
Niacin, also known as nicotinic acid or vitamin B3, is a water-soluble vitamin
discovered by Conrad Elvehjem in 1937. Its derivatives, NADH, NAD, NAD+, and
NADP plays essential roles in energy metabolism in the living cell and DNA repair (an
enzymatic process in a living cell). [1] The designation vitamin B3 also includes the
corresponding amide nicotinamide (or "niacinamide"), whose chemical formula is
C6H6NO2.
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Other functions of niacin include removing toxic chemicals from the body,[2] and
assisting in the production of steroid hormones made by the adrenal gland, such as sex
hormones and stress-related hormones.
2.2.9 Phosphorus
Phosphorus, (IPA: /ˈfɒsfərəs/, Greek: phôs meaning "light", and phoros meaning
"bearer"), is the chemical element that has the symbol P and atomic number 15. A
multivalent nonmetal of the nitrogen group, phosphorus is commonly found in inorganic
phosphate rocks.
Due to its high reactivity, phosphorus is never found as a free element in nature.
One form of phosphorus (white phosphorus) emits a faint glow upon exposure to oxygen
(hence its Greek derivation and the Latin 'light-bearer', meaning the planet Venus as
Hesperus or "Morning Star").
Phosphorus is a component of DNA and RNA and an essential element for all
living cells. The most important commercial use of phosphorus-based chemicals is the
production of fertilizers.
Phosphorus compounds are also widely used in explosives, nerve agents, friction
matches, fireworks, pesticides, toothpaste, and detergents.
2.2.10 Ash
In analytical chemistry, Ash is the name given to all compounds that are not
considered organic or water. These are the compounds that remain (as "ashes") after a
sample is burned, and consist mostly of metal oxides.
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Ash is one of the components in the proximate analysis of biological materials,
consisting mainly of salty, non-organic constituents. It includes metal salts which are
important for processes requiring ions such as Na+ (Sodium), K+ (Potassium), Ca+
(Calcium). It also includes trace minerals which are required for unique molecules, such
as chlorophyll and hemoglobin.
2.2.11 Starch
Starch (chemical formula (C6H10O5)) is a mixture of amylose and amylopectin
(usually in 20:80 or 30:70 ratios). These are both complex carbohydrate polymers of
glucose (chemical formula of glucose C6H12O6), making starch a glucose polymer as
well, as seen by the chemical formula for starch, regardless of the ratio of
amylose:amylopectin.
The word is derived from Middle English sterchen, meaning to stiffen, which is
appropriate since it can be used as a thickening agent when dissolved in water and heated.
2.2.11.1 Starch in food
In terms of human nutrition, starch is by far the most consumed
polysaccharide in the human diet. It constitutes more than half of the
carbohydrates even in many affluent diets, and much more in poorer diets.
Traditional staple foods such as cereals, roots and tubers are the main source of
dietary starch.
Starch (in particular cornstarch) is used in cooking for thickening foods
such as sauces. In industry, it is used in the manufacturing of adhesives, paper,
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textiles and as a mold in the manufacture of sweets such as wine gums and jelly
beans. It is a white powder, and depending on the source, may be tasteless and
odorless.
Starch is often found in the fruit, seeds, rhizomes or tubers of plants and is
the major source of energy in these food items. The major resources for starch
production and consumption worldwide are rice, wheat, corn, and potatoes.
Cooked foods containing starches include boiled rice, various forms of bread and
noodles (including pasta).
As an additive for food processing, arrowroot and tapioca are commonly
used as well. Commonly used starches around the world are: arracacha,
buckwheat, banana, barley, cassava, kudzu, oca, sago, sorghum, and regular
household potatoes (sweet potato, taro and yams). Edible beans, such as favas,
lentils and peas, are also rich in starch.
When a starch is pre-cooked, it can then be used to thicken cold foods.
This is referred to as a pre-gelatinized starch. Otherwise starch requires heat to
thicken, or “gelatinize”. The actual temperature needed depends on the type of
starch.
A modified food starch undergoes one or more chemical modifications,
which allow it to function properly under high heat and/or shear that is frequently
encountered during food processing. Food starches are typically used as
thickeners and stabilizers in foods such as puddings, custards, soups, sauces,
gravies, pie fillings, and salad dressings, but have many other uses.
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Resistant starch is a starch that escapes digestion in the small intestine of
healthy individuals.
Plants use starch as a way to store excess glucose, and thus also use starch
as food during mitochondrial oxidative phosphorylation.
Starch as adhesive in Papermaking is the largest non-food application for
starches globally, consuming millions of metric tons annually. In a typical sheet
of copy paper for instance, the starch content may be as high as 8%. Both
chemically modified and unmodified starches are used in papermaking. In the wet
part of the papermaking process, generally called the “wet-end”, starches are
chemically modified to contain a cationic or positive charge bound to the starch
polymer, and are utilized to associate with the anionic or negatively charged paper
fibers and inorganic fillers.
These cationic starches impart the necessary strength properties for the
paper web to be formed in the papermaking process (wet strength), and to provide
strength to the final paper sheet (dry strength). In the dry end of the papermaking
process the paper web is rewetted with a solution of starch paste that has been
chemically, or enzymatically depolymerized. The starch paste solutions are
applied to the paper web by means of various mechanical presses (size press). The
dry end starches impart additional strength to the paper web and additionally
provide water hold out or “size” for superior printing properties.
Corrugating glues are the next largest consumer of non-food starches
globally. These glues are used in the production of corrugated fiberboard
(sometimes called corrugated cardboard), and generally contain a mixture of
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chemically modified and unmodified starches that have been partially gelatinized
to form an opaque paste. This paste is applied to the flute tips of the interior fluted
paper to glue the fluted paper to the outside paper in the construction of cardboard
boxes. This is then dried under high heat, which provides the box board strength
and rigidity.
Another large non-food starch application is in the construction industry
where starch is used in the or wall board manufacturing process. Chemically
modified or unmodified starches are added to the rock mud containing primarily
gypsum. Top and bottom heavyweight sheets of paper are applied to the mud
formulation and the process is allowed to heat and cure to form the eventual rigid
wall board. The starches act as a glue for the cured gypsum rock with the paper
covering and also provide rigidity to the board.
2.2.12 pH
PH is a measure of the acidity or alkalinity of a solution. Aqueous solutions at
25°C with a pH less than seven are considered acidic, while those with a pH greater than
seven are considered basic (alkaline). When a pH level is 7.0, it is defined as 'neutral' at
25°C because at this pH the concentration of H3O+ equals the concentration of OH− in
pure water. PH is formally dependent upon the activity of hydronium ions (H3O+),[1] but
for very dilute solutions, the molarity of H3O+ may be used as a substitute with little loss
of accuracy (H+ is often used as a synonym for H3O+). Because pH is dependent on ionic
activity, a property which cannot be measured easily or fully predicted theoretically, it is
difficult to determine an accurate value for the pH of a solution. The pH reading of a
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solution is usually obtained by comparing unknown solutions to those of known pH, and
there are several ways to do so.
2.2.13 Yeast and Molds
2.3.13.1 Yeast
Yeasts are growth form of eukaryotic micro organisms classified in the kingdom
Fungi, with about 1,500 species described; they dominate fungal diversity in the oceans.
Most reproduce asexually by budding, although a few do by binary fission. Yeasts are
unicellular, although some species with yeast forms may become multicellular through
the formation of a string of connected budding cells known as pseudohyphae, or true
hyphae as seen in most molds. Yeast size can vary greatly depending on the species,
typically measuring 3–4 µm in diameter, although some yeasts can reach over 40 µm.
2.2.13.2 Molds
Moulds (or molds, see spelling differences) include all species of microscopic
fungi that grow in the form of multicellular filaments, called hyphae. In contrast,
microscopic fungi that grow as single cells are called yeasts. A connected network of
these tubular branching hyphae has multiple, genetically identical nuclei and is
considered a single organism, referred to as a colony or in more technical terms a
mycelium.
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2.3 Flour
2.3.1 History
Historically, both large and hand mills were operated to make flour. Until modern
times, much flour contained minute amounts of grit, either the result of poor sifting of the
grain or of grinding stones together. This grit strongly abraded teeth.
One of the most ancient methods of grinding to produce flour was by using a pair
of quern-stones. These were made out of rock, and were ground together by hand. They
were generally replaced by millstones once mechanised forms of milling appeared,
particularly the water mill and the windmill, although animals were also used to operate
the millstones.
2.3.2 Definition
An ingredient used in many foods, flour is a fine powder made from cereals or
other starchy food sources. It is most commonly made from wheat, but also maize (now
called corn in many parts of the Western Hemisphere), rye, barley, and rice, amongst
many other grasses and non-grain plants (including buckwheat, grain amaranths and
many Australian species of acacia). Flour is the key ingredient of bread, which is the
staple food in many countries, and therefore the availability of adequate supplies of flour
has often been a major economic and political issue. Flour can also be made from
legumes and nuts, such as soy, peanuts, almonds, and other tree nuts.
Flour is always based on the presence of starches, which are complex
carbohydrates (aka polysaccharides).
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Usually, the word "flour" used alone refers to wheat flour, which is one of the
most important foods in European and American culture and it usually is enriched. Wheat
flour is the main ingredient in most types of breads and pastries. Wheat flour was often
called corn before the introduction of corn from the Western Hemisphere.
Wheat is so widely used because of an important property: when wheat flour is
mixed with water, a complex protein called gluten develops. The gluten development is
what gives wheat dough an elastic structure that allows it to be worked in a variety of
ways, and which allows the retention of gas bubbles in an intact structure, resulting in a
sponge-like texture to the final product. This is highly desired for breads, cakes and other
baked products. However, certain individuals suffer from an intolerance to wheat gluten
known as coeliac or celiac disease. Increased awareness of this disorder, as well as a
rising belief in the benefits of a gluten-free diet for persons suffering certain other
conditions, has led to an increased demand for bread, pasta, and other products made with
flours that do not contain gluten.
A coarser, somewhat granular preparation, rather than a fine dust of flour is often
called meal.
2.3.3 Types of Flour
2.3.3.1 Wheat Flour
The vast majority of today's flour consumption is wheat flour.
Wheat varieties are typically known as, variously, "white" or "brown" if they have
high gluten content, and "soft" or "weak flour" if gluten content is low. Hard flour, or
"bread" flour, is high in gluten and so forms a certain toughness that holds its shape well
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once baked. Soft flour is comparatively low in gluten and so results in a finer texture.
Soft flour is usually divided into cake flour, which is the lowest in gluten, and pastry
flour, which has slightly more gluten than cake flour.
2.3.3.2 All-purpose or plain flour
This flour is a blended wheat flour with an intermediate gluten level which is
marketed as an acceptable compromise for most household baking needs.
In terms of the parts of the grain (the grass seed) used in flour—the endosperm or
starchy part, the germ or protein part, and the bran or fiber part—there are three general
types of flour. White flour is made from the endosperm only. Whole grain flour is made
from the entire grain including bran, endosperm, and germ. A germ flour is made from
the endosperm and germ, excluding the bran.
2.3.3.3 Bleached flour
This is a flour that was subjected to flour bleaching agents for health purposes, to
whiten it (freshly milled flour is yellowish), and to give it more gluten-producing
potential. Oxidizing agents are usually employed, most commonly organic peroxides like
acetone peroxide or benzoyl peroxide, nitrogen dioxide, or chlorine. A similar effect can
be achieved by letting the flour slowly oxidize with oxygen in the air ("natural aging")
for approximately 10 days; this process, however is more expensive due to the time
required.
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2.3.3.4 Bromated flour
This is flour with a maturing agent added. The agent's role is to help with
developing gluten, a role similar to the flour bleaching agents. Bromate is usually used.
Other choices are phosphates, ascorbic acid, and malted barley. Bromated flour has been
banned in much of the world, but remains available in the United States.
2.3.3.5 Cake flour
This is a finely milled flour made from soft wheat. It has very low gluten content,
making it suitable for soft-textured cakes and cookies. The higher gluten content of other
flours would make the cakes tough.
2.3.3.6 Graham flour
This is a special type of whole-wheat flour. The endosperm is finely ground, as in
white flour, while the bran and germ are coarsely ground. Graham flour is uncommon
outside of the USA and the cities of Romania. It is the basis of true graham crackers.
Many graham crackers on the market are actually imitation grahams because they do not
contain graham flour or even whole-wheat flour.
2.3.3.7 Pastry flour / cookie flour / cracker flour
This flour has slightly higher gluten content than cake flour, but lower than all-
purpose flour. It is suitable for fine, light-textured pastries.
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2.3.3.8 Self-rising or self-raising flour
This is "white" wheat flour or wholemeal flour that is sold premixed with
chemical leavening agents. It was invented by Henry Jones. It can also be substituted by
Maida when cooking under the Indian Cuisine. Typical ratios are:
U.S. customary:
one cup flour
1 to 1½ teaspoon baking powder
a pinch to ½ teaspoon salt
Metric:
100 g flour
3 g baking powder
1 g or less salt
2.3.3.9 Durum flour
This flour is made of durum wheat. It has the highest protein content, and it is an
important component of nearly all noodles and pastas. It is also commonly used to make
Indian flatbreads.
Wheat flour is highly explosive when airborne. In medieval flour mills, candles,
lamps, or other sources of fire were forbidden.
In Britain, many flours go by names different than those from America. Some
American flours and British equivalents include:
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Cake and pastry flour = soft flour
All-purpose flour = plain flour
Bread flour = strong flour, hard flour
Self-rising flour = self-raising flour
Whole-wheat flour = whole meal flour
2.3.4 Other Flours
2.3.4.1 Corn (maize) flour is popular in the Southern and Southwestern US
and in Mexico. Coarse whole-grain corn flour is usually called corn meal. Corn meal that
has been bleached with lye is called masa harina (see masa) and is used to make tortillas
and tamales in Mexican cooking. Corn flour should never be confused with cornstarch,
which is known as "corn flour" in British English.
2.3.4.2 Rye flour is used to bake the traditional sourdough breads of
Germany and Scandinavia. Most rye breads use a mix of rye and wheat flours because
rye has a low gluten content. Pumpernickel bread is usually made exclusively of rye, and
contains a mixture of rye flour and rye meal.
2.3.4.3 Rice flour is of great importance in Southeast Asian cuisine. Also,
edible rice paper can be made from it. Most rice flour is made from white rice, thus is
essentially a pure starch, however whole-grain brown rice flour is commercially
available.
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2.3.4.4 Noodle flour is special blend of flour used for the making of Asian
style noodles.
2.3.4.5 Buckwheat flour is used as an ingredient in many pancakes in the
United States. In Japan, it is used to make a popular noodle called Soba. In Russia,
buckwheat flour is added to the batter for pancakes called blinis which are frequently
eaten with caviar.
2.3.4.6 Chestnut flour is popular in Corsica, the Périgord and Lunigiana.
In Corsica, it is used to cook the local variety of polenta. In Italy, it is mainly used for
desserts.
2.3.4.7 Chickpea flour (also known as gram flour or besan) is of great
importance in Indian cuisine, and in Italy, where it is used for the Ligurian farinata.
2.3.4.8 Teff flour is made from the grain teff, and is of considerable
importance in eastern Africa (particularly around the horn of Africa). Notably, it is the
chief ingredient in the bread injera, an important component of Ethiopian cuisine.
2.3.4.9 Atta flour is wheat flour which is important in Indian cuisine, used
for a range of breads such as roti and chapati.
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2.3.4.10 Tang flour (not to be confused with the powdered beverage Tang)
or wheat starch is a type of wheat flour used primarily in Chinese cooking for making the
outer layer of dumplings and buns.
2.3.4.11 Glutinous rice flour or sticky rice flour, used in east and southeast
Asian cuisines for making tangyuan etc.
2.3.4.12 Peasemeal or pea flour is flour produced from roasted and
pulverized yellow field peas.
2.3.4.13 Bean flour is flour produced from pulverized dried or ripe beans.
2.3.4.14 Potato flour is obtained by grinding the tubers to a pulp and
removing the fibre by water-washings. The dried product is consist chiefly of starch, but
also contains some protein. Potato flour is used as a thickening agent. When heated and
brought to boiling, food added with a suspension of potato flour in water thickens
quickly. Because the flour is made from neither grain nor legume, it is used as substitute
for wheat flour in cooking by Jews during Passover, when grains are not eaten.
2.3.4.15 Amaranth flour is flour produced from ground Amaranth grain. It
was commonly used in pre-Columbian meso-American cuisine. It is becoming more and
more available in specialty food shops.
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2.3.4.16 Nut flours are ground from oily nuts--most commonly almonds
and hazelnuts--and are used instead of or in addition to wheat flour to produce more dry
and flavorful pastries and cakes. Cakes made with nut flours are usually called tortes and
mostly originated from Central Europe, in countries such as Hungary and Austria.
Flour can also be made from buckwheat, soy beans, arrowroot, taro, cattails,
acorns, peas, beans, and other non-grain foodstuffs.
2.3.5 Flour type numbers
In some markets, the different available flour varieties are labeled according to
the ash mass ("mineral content") that remains after a sample was incinerated in a
laboratory oven (typically at 550 °C or 900 °C, see international standards ISO 2171 and
ICC 104/1). This is an easy to verify indicator for the fraction of the whole grain that
ended up in the flour, because the mineral content of the starchy endosperm is much
lower than that of the outer parts of the grain. Flour made from all parts of the grain
(extraction rate: 100%) leaves about 2 g ash or more per 100 g dry flour. Plain white flour
(extraction rate: 50-60%) leaves only about 0.4 g.
2.3.5.1 German flour type numbers (Mehltype) indicate the amount of ash
(measured in milligrams) obtained from 100 g of the dry mass of this flour. Standard
wheat flours (defined in DIN 10355) range from type 405 for normal white wheat flour
for baking, to strong bread flour types 550, 650, 812, and the darker types 1050 and 1600
for wholegrain breads.
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2.3.5.2 French flour type numbers (type de farine) are a factor 10 smaller than
those used in Germany, because they indicate the ash content (in milligrams) per 10 g
flour. Type 55 is the standard, hard-wheat white flour for baking, including puff pastries
("pâte feuilletée"). Type 45 is often called pastry flour, but is generally from a softer
wheat. Types 65, 80, and 110 are strong bread flours of increasing darkness, and type 150
is a wholemeal flour.
In the United States and the United Kingdom, no numbered standardized flour
types are defined, and the ash mass is only rarely given on the label by flour
manufacturers. However, the legally required standard nutrition label specifies the protein
content of the flour, which is also a suitable way for comparing the extraction rates of
different available flour types.
It is possible to find out ash content from some US manufacturers. However, US
measurements are based on wheat with a 14% moisture content. Thus, a US flour
with .48 ash would approximate a French Type 55.
In general, as the extraction rate of the flour increases, so do both the protein and
the ash content. However, as the extraction rate approaches 100% (whole meal), the
protein content drops slightly, while the ash content continues to rise.
The following table shows some typical examples of how protein and ash content
relate to each other in wheat flour:
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Table 1: This table shows the Protein and Ash Content of Flours
Ash Protein Wheat flour type
US German French
~0.4% ~9% pastry flour 405 45
~0.55% ~11% all-purpose flour 550 55
~0.8% ~14% high gluten flour 812 80
~1% ~15% first clear flour 1050 110
>1.5% ~13% white whole wheat 1600 150
This table is only a rough guideline for converting bread recipes. Since the
American flour types are not standardized, the numbers may differ between
manufacturers.
2.3.6 Flour Production
Milling of flour is accomplished by grinding grain between stones or steel wheels.
Today, "stone-ground" usually means that the grain has been ground in a mill in which a
revolving stone wheel turns over a stationary stone wheel, vertically or horizontally with
the grain in between. Many small appliance mills are available, both hand-cranked and
electric.
Flour dust suspended in air is explosive, as is any mixture of a finely powdered
flammable substance with air. Some devastating and fatal explosions have occurred at
flour mills, including an explosion in 1878 at the Washburn "A" Mill in Minneapolis, the
largest flour mill in the United States at the time.
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2.3.7 Flour Products
Bread, pasta crackers, many cakes, and many other foods are made using flour.
Wheat flour is also used to make a roux as a base for gravy and sauces. White wheat flour
is the traditional base for wallpaper paste. It is also the base for papier-mâché. Cornstarch
is a principal ingredient of many puddings or desserts.
2.3.8 Flour Contamination
The exteriors of harvested grains retain some of the microorganisms they
had while the growing plus contamination from soil, insects, and other sources. Freshly
harvested grains contain a few thousand to millions of bacteria per gram and from none
to several hundred thousands mold spores. Bacteria are mostly from the families
Pseudomonadaceae, Lactobacillceae, micrococcaceae and Bacillaceae. Bacteria in
wheat flour include spores of Bacillus, coliform bacteria, and a few representatives of the
genera Achromobacter, Flavobacterium, Sarcina, Micrococcus, Alcaligenes, and
Serratia.
Dry cleaning and washing of grains and the milling and sifting of flour reduced
the content of microorganisms, but the important kinds still are represented in whole
grain flour. White wheat flour, however, usually is bleached by an oxidizing agent, such
as an oxide of nitrogen, chlorine nitrosyl chloride, or benzoyl peroxide, and this process
serves to reduce microbial numbers and kinds. A moisture content of a flour of less than
13% has been reported to prevent the growth of all microorganisms. Other workers claim
that 15% permits good mold growth, and over 17% the growth of all molds and bacteria.
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2.4 Bread
Bread is the staple food of European, Middle Eastern and Indian cultures which is
prepared by baking, steaming, or frying of dough. Bread consists minimally of flour and
water; salt is present in most cases, and usually a leavening agent such as yeast is used.
Bread may also contain some amounts of sugar, spices, fruit (such as raisins, pumpkin or
bananas), vegetables (like onion or zucchini), nuts, or seeds (such as caraway, sesame or
poppy seeds). There are a wide variety of breads, with preferences differing from region
to region.
Fresh bread is prized for its taste and texture, and retaining its freshness is
important to keep it appetizing. Bread that has stiffened or dried past its prime is said to
be stale. Modern bread is often wrapped in paper or plastic film, or stored in airtight
containers such as a breadbox to keep it fresh longer. Bread that is kept in warm moist
environments is prone to the growth of mold. It becomes stale more quickly in the low
temperature of a refrigerator, although by keeping it cool, mold is less likely to grow.
The inner soft part of bread is referred to as the crumb (not to be confused with
small bits of bread, which are called "crumbs"). The outer hard part of bread is called the
crust (The latter term is in common use, but "crumb" is an esoteric word used mainly by
culinary professionals.).
2.4.1 Usage
Bread can be served ranging anywhere from room temperature to hot. Once
baked, bread can subsequently be toasted. Bread is most commonly picked up and eaten
with the hands, or sometimes with a fork and knife. It can be eaten by itself or as a carrier
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for another, usually less compact food. Bread may be dunked or dipped into a liquid
(such as beef gravy or olive oil), topped with various spreads, both sweet and savory, or
serve as the enclosure for the ubiquitous sandwich with any number of meats, cheeses,
vegetables or condiments inside. Across the world, bread is the preferred vehicle for
many toppings that vary from culture to culture.
2.4.2 Etymology
The word itself, Old English bread, is common in various forms to many
Germanic languages; such as Frisian brea, Dutch brood, German Brot, Swedish bröd, and
Norwegian brød; it has been claimed to be derived from the root of brew, but more
probably is connected with the root of break, for its early uses are confined to broken
pieces, or bits of bread, the Latin crustum, and it was not until the 12th century that it
took the place—as the generic name for bread—of hlaf (modern English loaf), which
appears to be the oldest Teutonic name; Old High German hleib and modern German
Laib, or Finnish leipä, Estonian leib, and Russian хлеб (khleb) are similar (all are derived
from the Old Germanic word for "loaf").
2.4.3 History
Bread is one of the oldest prepared foods, dating back to the Neolithic era. The
first breads produced were probably cooked versions of a grain-paste, made from ground
cereal grains and water, and may have been developed by accidental cooking or
deliberate experimentation with water and grain flour. Descendants of these early breads
are still commonly made from various grains worldwide, including the Mexican tortilla,
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Indian chapatis, rotis and naans, Scottish oatcake, North American johnnycake, Middle
Eastern Pita bread (Kmaj in Arabic and Pitot in Hebrew) and Ethiopian injera. The basic
flat breads of this type also formed a staple in the diet of many early civilizations with the
Sumerians eating a type of barley flat cake, and the 12th century BC Egyptians being able
to purchase a flat bread called ta from stalls in the village streets.
2.4.4 Types
Bread is a popular food in Western and most other societies, although East Asian
societies typically prefer rice or noodles. It is often made from a wheat-flour dough that is
cultured with yeast, allowed to rise, and finally baked in an oven. Owing to its high levels
of gluten (which give the dough sponginess and elasticity), common wheat (also known
as bread wheat) is the most common grain used for the preparation of bread, but bread is
also made from the flour of other wheat species (including durum, spelt and emmer), rye,
barley, maize (or corn), and oats, usually, but not always, in combination with wheat
flour. Although common wheat is best suited for making highly-risen white bread, other
wheat species are capable of giving a good crumb. Spelt bread (Dinkelbrot) continues to
be widely consumed in Germany, and emmer bread was a staple food in ancient Egypt.
2.4.5 Composition and chemistry
2.4.5.1 Formulation
The amount of water and flour are the most significant measurements in a bread
recipe, as they affect texture and crumb the most. Professional bakers use a system of
percentages known as Bakers' Percentage in their recipe formulations, and measure
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ingredients by weight instead of by volume. Measurement by weight is much more
accurate and consistent than measurement by volume, especially for the dry ingredients.
Flour is always 100%, and the rest of the ingredients are a percent of that amount
by weight. Common table bread in the U.S. uses approximately 50% water, resulting in a
finely-textured, light, bread. Most artisan bread formula contain anywhere from 60 to
75% water. In yeast breads, the higher water percentages result in more CO2 bubbles,
and a coarser bread crumb. One pound (500 g) of flour will yield a standard loaf of bread,
or two French loaves.
Calcium propionate is commonly added by commercial bakeries to retard the
growth of molds.
2.4.5.2 Flour
Flour is a product made from grain that has been ground into a powdery
consistency. It is flour that provides the primary structure to the final baked bread.
Commonly available flours are made from rye, barley, maize, and other grains, but it is
wheat flour that is most commonly used for breads. Each of these grains provides the
starch and protein necessary for the production of bread.
The quantity and quality of the proteins contained in the flour determine the
quality of the bread dough and the finished bread. While bread can be made from all-
purpose wheat flour, for quality bread a specialty bread flour, containing more protein, is
recommended.
Wheat flour in addition to its starch, contains three water-soluble proteins groups,
albumin, globulin, proteoses, and two non-water soluble proteins groups, glutenin and
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gliadin. When flour is mixed with water, the water-soluble proteins dissolve, leaving the
glutenin and gliadin to form the structure of the resulting dough. When worked by
kneading, the glutenin forms strands of long thin chainlike molecules while the shorter
gliadin forms bridges between the strands of glutenin. The resulting networks of strands
produced by these two proteins is known as gluten. Gluten development improves if the
dough is allowed to autolyse.
2.4.5.3 Liquids
Water, or some other liquid, is used to form the flour into a paste or dough. The
volume of liquid required varies between recipes, but a ratio of 1 part liquid to 3 parts
flour is common for yeast breads while recipes that use steam as the primary leavening
method may have a liquid content in excess of one part liquid to one part flour by
volume. In addition to water, other types of liquids that may be used include dairy
products, fruit juices, or beer. In addition to the water in each of these they also bring
additional sweeteners, fats, and or leavening components.
2.4.5.4 Leavening
Leavening is the process of adding gas to a dough before or during baking to
produce a lighter, more easily chewed bread. Most bread consumed in the West is
leavened. However, unleavened breads have symbolic importance in Judaism and
Christianity. Jews consume unleavened bread called Matza during Passover. They are
also used in the Christan liturgy when they perform the Eucharist, a rite derived from the
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narrative of the Last Supper when Jesus broke bread with his disciples during a Passover
Seder.
2.4.5.4.1 Chemical leavening
A simple technique for leavening bread is the use of gas-producing chemicals.
There are two common methods. The first is to use baking powder or a self-rising flour
that includes baking powder. The second is to have an acidic ingredient such as
buttermilk and add baking soda. The reaction of the acid with the soda produces gas.
Chemically-leavened breads are called quick breads and soda breads. This
technique is commonly used to make muffins, pancakes, American-style biscuits and
sweet breads such as banana bread.
2.4.5.4.2 Yeast leavening
Many breads are leavened by yeast. The yeast used for leavening bread is
Saccharomyces cerevisiae, the same species used for brewing alcoholic beverages. This
yeast ferments carbohydrates in the flour, including any sugar, producing carbon dioxide.
Most bakers in the U.S. leaven their doughs with commercially produced baker's yeast.
Baker's yeast has the advantage of producing uniform, quick, and reliable results, because
it is obtained from a pure culture. Many artisan bakers produce their own yeast by
preparing a 'growth culture' which they then use in the making of bread. This culture kept
in the right conditions will continue to grow and provide leavening for many years
Both the baker's yeast, and the sourdough method of baking bread follow the
same pattern. Water is mixed with flour, salt and the leavening agent (baker's yeast or
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sourdough starter). Other additions (spices, herbs, fats, seeds, fruit, etc.) are not necessary
to bake bread, but often used. The mixed dough is then allowed to rise one or more times
(a longer rising time results in more flavor, so bakers often punch down the dough and let
it rise again), then loaves are formed and (after an optional final rising time) the bread is
baked in an oven.
Many breads are made from a straight dough, which means that all of the
ingredients are combined in one step, and the dough is baked after the rising time.
Alternatively, doughs can be made with the starter method, when some of the flour,
water, and the leavening are combined a day or so ahead of baking, and allowed to
ferment overnight (such as the poolish typically used for baguettes). On the day of the
baking, the rest of the ingredients are added, and the rest of the process is the same as that
for straight doughs. This produces a more flavorful bread with better texture. Many
bakers see the starter method as a compromise between the highly reliable results of
baker's yeast, and the flavor/complexity of a longer fermentation. It also allows the baker
to use only a minimal amount of baker's yeast, which was scarce and expensive when it
first became available.
2.4.5.4.3 Sourdough
The sour taste of sourdoughs actually comes not from the yeast, but from a
lactobacillus, with which the yeast lives in symbiosis. The lactobacillus feeds on the
byproducts of the yeast fermentation, and in turn makes the culture go sour by excreting
lactic acid, which protects it from spoiling (since most microbes are unable to survive in
an acid environment). All yeast-leavened breads used to be sourdoughs, and the
39
leavening process was not understood until the 19th century, when with the advance of
microscopes, scientists were able to discover the microbes that make the dough rise.
Since then, strains of yeast have been selected and cultured mainly for reliability and
quickness of fermentation. Billions of cells of these strains are then packaged and
marketed as "Baker's Yeast". Bread made with baker's yeast is not sour because of the
absence of the lactobacillus. Bakers around the world quickly embraced baker's yeast for
it made baking simple and so allowed for more flexibility in the bakery's operations. It
made baking quick as well, allowing bakeries to make fresh bread from scratch as often
as three times a day. While European bakeries kept producing sourdough breads, in the
U.S., sourdough baking was widely replaced by baker's yeast, and only recently has that
country (or parts of it, at least) seen the rebirth of sour-vinegar dough in artisan bakeries.
According to Alton Brown, host of Food Network's "Good Eats" television show, each
region of the world has different strains of lactobacillus, hence the flavor of the bread
made from home starters is unique. The San Francisco Bay area is especially famous for
its sourdough breads.
Sourdough breads are most often made with a sourdough starter (not to be
confused with the starter method discussed above). A sourdough starter is a culture of
yeast and lactobacillus. It is essentially a dough-like or pancake-like flour/water mixture
in which the yeast and lactobacilli live. A starter can be maintained indefinitely by
periodically discarding a part of it and refreshing it by adding fresh flour and water.
(When refrigerated, a starter can go weeks without needing to be fed.) There are starters
owned by bakeries and families that are several human generations old, much revered for
creating a special taste or texture. Starters can be obtained by taking a piece of another
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starter and growing it, or they can be made from scratch. There are hobbyist groups on
the web who will send their starter for a stamped, self-addressed envelope, and there are
even mailorder companies that sell different starters from all over the world. An acquired
starter has the advantage to be more proven and established (stable and reliable, resisting
spoiling and behaving predictably) than from-scratch starters.
There are other ways of sourdough baking and culture maintenance. A more
traditional one is the process that was followed by peasant families throughout Europe in
past centuries. The family (usually the woman was in charge of breadmaking) would
bake on a fixed schedule, perhaps once a week. The starter was saved from the previous
week's dough. The starter was mixed with the new ingredients, the dough was left to rise,
then a piece of it was saved (to be the starter for next week's bread). The rest was formed
into loaves which were marked with the family sign (this is where today's decorative
slashing of bread loaves originates from), and taken to the communal oven to bake. These
communal ovens over time evolved into what we know today as bakeries, when certain
people specialized in bread baking, and with time enhanced the process so far as to be
able to mass produce cheap bread for everyone in the village.
2.4.5.4.4 Steam leavening
The rapid expansion of steam produced during baking leavens the bread, which is
as simple as it is unpredictable. The best known steam-leavened bread is the popover.
Steam-leavening is unpredictable since the steam is not produced until the bread is baked.
Steam leavening happens regardless of the rising agents (soda powder, yeast,
baking-powder, sour dough, egg snow.).
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These rising agent generate carbon dioxide - or already contains air bubbles.
The heat vaporises the water from the inner surface of the bubbles within the
dough.
The steam expands and makes the bread rise.
It is actually the main factor in the rise of bread once it has been put in the oven.
CO2 generation, on its own, is too small to account for the rise. Heat kills bacteria or
yeast at an early stage, so the CO2 generation is stopped.
2.4.5.4.5 Bacterial leavening
Salt-risen bread employs a form of bacterial leavening that does not require yeast.
Although the leavening action is not always consistent, and requires close attention to the
incubating conditions, this bread is making a comeback due to its unique cheese-like
flavor and fine texture.
2.4.5.4.6 Aeration
Aerated bread is leavened by carbon dioxide being forced into dough under
pressure. The technique is no longer in common use, but from the mid 19th to 20th
centuries bread made this way was somewhat popular in the United Kingdom, made by
the Aerated Bread Company and sold in its high-street tea rooms.
2.4.5.5 Fats or shortenings
Fats such as butter, vegetable oils, lard, or that contained in eggs affects the
development of gluten in breads by coating and lubricating the individual strands of
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protein and also helping hold the structure together. If too much fat is included in a bread
dough, the lubrication effect will cause the protein structures to divide. A fat content of
approximately 3% by weight is the concentration that will produce the greatest leavening
action.
This effect is used most popularly in cookies, in that increased fat - typically
shortening - causes a harder cookie (more popular in cookies such as chocolate chip)
while increased flour causes a softer cookie (more popular in cookies such as oatmeal).
As it is typically not acceptable to have harder bread, this effect is usually not available
for use in breads.
In addition to their effects on leavening, fats also serve to tenderize the breads
they are used in and also help to keep the bread fresh longer after baking.
2.4.5.6 Bread Improvers
Bread improver is commonly used in production of bread to speed up the time
that the bread takes to rise and it helps improve the texture and the volume of bread.
2.5 Muffin
2.5.1 Definition
A muffin is a small cake, resembling a cupcake: they have cylindrical bases,
rounded conical tops, and are usually sweet, although savory varieties (such as cornbread
muffins) also exist. They generally fit in the palm of an adult hand, and are intended to be
consumed by an individual in a single sitting. A muffin can also mean a different baked
good, the smaller, disk-shaped English muffin, although this usage is uncommon outside
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Britain. As American style muffins are now sold in the UK, the term can refer to either
product, the context usually making clear which is meant. There are many varieties and
flavors of muffins made with a specific ingredient such as blueberries or chocolate chips.
These ingredients are then baked into the muffin.
2.5.2 Early History
The "quick" muffins may have started out as a form of small cake, or possibly an
adaptation of cornbread. Early versions of these muffins tend to be less sweet and much
less varied in ingredients than their contemporary forms. Made quickly and easily, they
were useful as a breakfast food. They also rapidly grew stale, which prevented them from
being a marketable baked good, and they were not seen much outside home kitchens until
the mid-20th century. Recipes tended to be limited to different grains (corn, wheat bran,
or oatmeal) and a few readily available additives (raisins, apples in some form, or nuts).
Fannie Merritt Farmer listed 15 recipes of this type in her Boston Cooking-School Cook
Book of 1896, of which there were two each of "one-egg", "berry", oat, graham flour, and
rye; one with cornmeal, one with cooked rice, and the remaining three slightly enriched
versions of the plain "one-egg" muffin.
Farmer used the term gem for her corn recipe, which was a muffin baked in a pan
of lozenge shapes rather than circular cups. With the invention of circular muffin paper
cups, hard-to-clean iron gem pans lost popularity, and are rarely used today, although
corn muffins baked in the form of ears of corn remain a tradition. The development of
non-stick pans has allowed the production of very elaborate muffin shapes (animals,
holiday motifs, etc.), but the circular muffin remains the norm.
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In the 1950s, packaged muffin mixes were introduced by several companies, most
noticeably Spacey's (American) and Cadbury (British). By the 1960s, attempts were
being made to treat the muffin like the doughnut as a franchise food business opportunity.
Coffee shop-style restaurant chains appeared, featuring a wide variety of muffins. These
tended to be regional, such as The Pewter Pot in southern New England. No such
business has emerged nationally in the US (although doughnut chains have edged into the
business), but Australia's Muffin Break has spread to New Zealand and the UK, featuring
the American-style muffin.
2.5.3 Modern History
A somewhat odd combination of circumstances in the 1970s and 1980s led to
significant changes in what had been a rather simple, if not prosaic, food. The decline in
home-baking, the health food movement, the rise of the specialty food shop, and the
gourmet coffee trend all contributed to the creation of a new standard of muffin.
Preservatives in muffin mixes led to the expectation that muffins did not have to
go stale within hours of baking, but the resulting muffins were not a taste improvement
over homemade. On the other hand, the baked muffin, even if from a mix, seemed almost
good for one compared to the fat-laden alternatives of doughnuts and Danish pastry.
"Healthful" muffin recipes using whole grains and such "natural" things as yogurt and
various vegetables evolved rapidly. But for "healthful" muffins to have any shelf-life
without artificial preservatives, the sugar and fat content needed to be increased, to the
point where the "muffins" are almost indistinguishable from cupcakes. The rising market
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for gourmet snacks to accompany gourmet coffees resulted in fancier concoctions in
greater bulk than the original modestly-sized corn muffin.
The marketing trend toward larger portion sizes also resulted in new muffin pan
types for home-baking, not only for increased size. Since the area ratio of muffin top to
muffin bottom changed considerably when the traditional small round exploded into a
giant mushroom, consumers became more aware of the difference between the soft
texture of tops, allowed to rise unfettered, and rougher, tougher bottoms, restricted by the
pans. There was a brief foray into pans that could produce "all-top" muffins, i.e.,
extremely shallow, large-diameter cups. However, the reality of muffin physics prevented
the fad from getting very far. The TV sitcom Seinfeld made reference to this in an
episode in which the character Elaine Benes co-owns a bakery named "Top o' the Muffin
to You!" that sold only the muffin tops (see The Muffin Tops (Seinfeld episode)). Along
with the increasing size of muffins is a contrary trend of extremely small muffins. It is
now very common to see muffin pans or premade muffins that are only one or two inches
in diameter. Companies like Trader Joe's and Lite Bites are among the industry leaders in
mini-muffin production.
2.5.4 Types of muffins
2.5.4.1 English Muffin
The traditional English muffin is very different from the American variety. The
English muffin is yeast leavened and predates the baking powder leavened muffins. This
produces a type of muffin with a thick, fluffy pastry and is usually baked as a disk
typically about 8 cm in diameter. It is usually split into two, toasted and buttered, and
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bears a vague resemblance to a crumpet or pikelet. It also is eaten cold with a hot drink at
coffee shops and diners. Fannie Farmer in her Cook Book gave recipes for both types of
muffins, distinguishing between "raised" and adding instructions for a version that is
nearly identical to today's "English muffin". Here the raised-muffin mixture was cooked
in muffin rings on a griddle, and flipped to brown both sides, producing a grilled muffin.
Farmer indicated this was a useful method when baking in an oven was not practical.
2.5.4.2 Corn Muffin
Muffins made from cornmeal are popular in the United States. Similar to
cornbread, they can be eaten with butter or as a side dish with stews or chili.
2.5.5 Muffin paper cups
Muffin paper cups are round sheets of paper, foil or metal, with scallop-pressed
edges, giving the muffin a round cup shape. Their shape can be compared to that of a
disposable coffee filter. Muffin paper cups are used to line the bottoms of muffin pans,
used in the baking of muffins to facilitate the easy removal of the finished pastry from the
muffin tin.
The advantage of cooking muffin cup is easier removal and cleanup, and moister
muffins; however, using them will prevent a crust. Organic variations of the muffin cup
are sold at Whole Foods.
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2.6 Health Benefits and Concerns
2.6.1 Aid in Reducing the Risk of Certain Disease
2.6.1.1 Asthma
Vitamin C, present in fruits and vegetables, is a powerful antioxidant and
inflammatory. This anti-inflammatory activity may influence the development of asthma
symptoms. A large preliminary study has shown that young children with asthma
experience significantly less wheezing if they eat a diet high in fruits rich in vitamin C.
2.6.1.2 Atherosclerosis
Diets high in insoluble fiber (found in some vegetables) are associated with
protection against heart disease in both men and women.
2.6.1.3 Athletic Performance
Carbohydrate food is the most efficient fuel for energy production and can also be
stored as glycogen in muscle and liver, functioning as a readily available energy source
for prolonged, strenuous exercise. For this reasons, carbohydrate maybe the most
important nutrient for sports performance. Depending on training intensity and duration.
Athletes require up to 4.5 grams of carbohydrates per day per pound of body weight or
60-70 % of total dietary calories from carbohydrates, which ever is greater. Including
starchy vegetables in the diet is one good way to obtain these carbohydrates.
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2.6.1.4 Bruising
Many Americans eat insufficient amounts of foods containing vitamin C; the
disease caused by vitamin C deficiency, scurvy, causes easy bruising. While very few
people actually have scurvy, even minor deficiencies of vitamin C an increase the
incidence in bruising. People who experience easy bruising may want to try eating more
fruits and vegetables-common dietary sources in vitamin C.
2.6.1.5 Cancer
The strong association between increased intake of beta-carotene from food and a
reduce risk of lung cancer does not necessarily mean that supplementation with natural
beta-carotene supplements would reduce the risk of lung cancer. Dietary beta-carotene
maybe a marker for diets high in certain fruits and vegetables that contain other anti-
cancer substances that maybe responsible for the protective effects. Until more is known,
some doctors advice smokers to avoid all forms of beta-carotene supplementation-even
natural beta-carotene.
2.6.1.6 Capillary Fragility
Eating plenty of flavonoid and vitamin C-rich fruits and vegetables helps to
support the structure of capillaries.
2.6.1.7 Cataracts
Some, but not all, studies have reported that eating more foods rich in beta-
carotene or vitamin A was associated with a lower risk of cataracts. Synthetic beta-
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carotene supplementation has not even found to reduce the risk of cataract formation. It
remains unclear whether natural beta-carotene from food or supplements would protect
the eye or whether beta-carotene in food is merely a marker for other protective factors in
fruits and vegetables high in beta-carotene.
2.6.1.8 High Homocysteine
A controlled trial showed that eating a diet high in fruits and vegetables
containing folic acid, beta-carotene and vitamin C effectively lowered homocysteine
levels. Healthy people were assigned to either a diet containing a pound of fruits and
vegetables per day, or to a diet containing 3 ½ ounces (99 grams) of fruits and vegetables
per day. After 4 weeks, those eating the higher amount of fruits and vegetables had a 11%
lower homocysteine level compared to those eating the lower amount of fruits and
vegetables.
2.6.1.9 Macular Degeneration
People who eat plenty of fruits and vegetables high in beta-carotene appear to be
at lower risk for muscular degeneration than people who do not eat these foods. However,
another study found no association between age-related muscular degeneration and intake
of anti-oxidants, either from diet, from supplements, or from combined. More research is
needed to reconcile these differences. In the mean time, beta-carotene-rich vegetables
continue to be part of healthful diet.
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2.6.1.10 Night Blindness
Low intake of fruits and vegetables containing beta-carotene, which the body
converts into vitamin A, may contribute to a vitamin A deficiency.
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2.7 Studies Conducted Previously
Table 2: This table shows the studies conducted previously in sweet potato.
Author Results
Agdeppa, Dr. Imelda Angeles Vital for muscle contraction, nerve impulses and
proper functioning of heart and kidneys; and helps
regulate blood pressure and water balance in cells.
Lack of potassium causes muscular weakness,
increase in nervous irritability, mental disorientation,
and cardiac irregularities. Excessive intake causes heart
block. Good sources are dried beans, dark green and
leafy vegetables, fish, shellfish, marine products, eggs,
and dairy products.
Gayya, Cynthia T Dietary fibers are provided in the human diet by
eating fruits, vegetables, grain products, legumes, nuts
and a variety of sources, usually from plant products.
Therefore, selecting fresh fruits, vegetables and other
high-fiber foods such as oatmeal, would represent both
an economic and nutritious means of adding bulk to
your diet. Although there is no recommended dietary
allowance set for adequacy of intake of dietary fibers, an
intake of 55-60% carbohydrate of total kilocalorie will
suffice for the needed amount of fibers in the body.
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2.8 Functional Properties of Sweet Potato and Sweet Potato Flour
Table 3: This table shows the functional properties of sweet potato
Chemical Composition per 100 g of Sweet Potato
Calories 400
Moisture 10 – 20 %
Protein 35.10 g
Fat 17.70 g
Total CHO 32.00 g
Fiber 4.20 g
Ash 5 g
Calcium 226 mg
Phosphorus 546 mg
Riboflavin 8.50 mg
Niacin 2.50 mg
*Acceptability studies of drop cookies prepared from composite flour (consisting of soya & sweet potato)
Galaro, Lolita C.; Gaspar, Ma. Thelma; and Mitra, Nelodina (Oct 1993)
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Table 4: This table shows the functional properties of sweet potato flour
*Properties %
Starch 71.7
Sugar 11.3
Protein 3.9
Fiber 10.3
Fat 0.6
Ash 1.89
Total 99.69
*Philippine Journal of Food Science and Technology
Volume 21., No. 2 July – December, 1999
L. S. Collado & H. Corke
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2.9 CONCEPTUAL FRAMEWORK
Input Process Output
Figure 1: This figure shows the Conceptual Framework of the Utilization of Sweet Potato “Ipomoea batatas” Flour in Bread Making
Selection andPreparation of raw materials and equipment
Procedure for bread making
Physico-chemical analysis
Stability and Sensory test
Quality, safe and nutritious Sweet Potato bread
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Gathering information and data.
Procedure for flour
Rich source of vitamins, minerals and fiber bread
Available and cheap bread product
Healthy citizenry
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