cereal psroduct

1. Cereal Products
The cereals most important in human food are wheat and rice. Wheat is consumed mostly as
baked products throughout the world.
Wheat and wheat products
(1) Wheat (Triticum)
 Wheat is used principally for human consumption. It is converted into flour for the
production of bread and other bakery products. It is used as "chapatti" in India.
 It belongs to the genus Triticum and there are over 30,000 species and varieties. The
principal wheats of commerce are the common or bread wheat (T. aestivum); macaroni
wheat (T. durum) and club wheat (T. compactum).
 In terms of area, India ranked fourth and in production fifth, among the wheat growing
countries of the world in 1980, but in 2017, it emerged as the second largest wheat
producing nation in the world. Production of major crops from 2013-16 listed in below
table:
 Approximately 90 per cent of wheat consumption in India is in the form of chapati. Bread
consumption also is showing signs of a significant annual increase. More than 1.5 million
tonnes of wheat are used in the production of bakery products.
(2) Composition of wheat: The chemical composition of the wheat kernel varies widely,
being influenced by environment, soil and variety. The values reported for Indian wheat are:
Moisture = 8.0-17.0 %
Starch = 63.0-71.0 %
Sugars = 2.0-3.0 %
Protein = 8.0-15.0 %
Crude fibre = 2.0-2.5 %
Fat = 1.5-2.0 % and
Ash = 1.5-2.0 %
Wheat is a good source of mineral nutrients. It contains a significant amount of iron,
phosphorus, magnesium, manganese, copper and zinc. It is also a good source of thiamine
and nicotinic acid, but is relatively poor in riboflavin.

2.  Amongst carbohydrates of wheat, practically all of the starch is in the endosperm, while
the soluble sugars are mostly found in the germ. The lipid content in endosperm (1-2 per
cent), bran (5-6 per cent) and germ (8-15 per cent) but the proportion of compound lipids
in the endosperm is much higher. The proteins of wheat may be divided into two major
groups:
Non-gluten protein: albumins and globulins
Gluten proteins: mainly gliadins and glutenins and insoluble residual proteins.
(3) Milling of Wheat
 Wheat is consumed mostly in the form of flour obtained by milling the grain while a small
quantity is converted into breakfast foods, such as wheat flakes, puffed wheat and
shredded wheat. Indian wheats have good milling properties. Barring some softer wheats,
Indian wheats are hard, flinty and of amber colour.
 The moisture content at harvest is low, usually 8-10 per cent.
 The traditional procedure for milling wheat in India has been stone grinding (chakki) to
obtain whole meal flour (atta). This method results in a 90-95 per cent extraction rate of
flour which retains almost all the nutrients of the grain while simultaneously eliminating
that part of the grain which is most indigestible like cellulose, and phytic acid which binds
and carries away minerals.
 Therefore, Indian style flour is not technically "whole wheat" but it is superior to the usual
whole grain flour that is produced by simply grinding everything to a fine powder.
 Stone grinding is gradually giving place to power driven small and big chakkis and to
modern flour mills.
 In modern milling, wheat is first subjected to cleaning to remove various types of
impurities together with damaged, shrunken and broken kernels which are collectively
known as "screenings".
 Impurities that adhere to the grain are removed by washing or by dry scouring which
loosens the impurities which are then blown away by an air current.

3.  Other impurities in the form of particles unattached to the grain are separated by making
use of characteristics in which the impurities differ from wheat. These include separation
based on differences in size, shape, terminal velocity in air currents, specific gravity,
magnetic and electrostatic properties, colour, surface roughness, etc. The total quantity of
screenings removed generally amounts to 1—1
1
2
per cent of the grain fed to the machine.
 Next, the cleaned wheat is subjected to conditioning. This improves the physical state of
the grain for milling, and sometimes improves the baking quality of the milled flour. The
process involves adjustment of the average moisture content of the wheat. When the
moisture content is optimum (i.e., 15-17 per cent), the bran is toughened and separation of
the endosperm from the bran becomes easy.
 Finally, the cleaned and conditioned wheat is subjected to milling to separate the
endosperm from the bran and germ, and to reduce the endosperm to flour fineness to
obtain the maximum extraction of white flour from the wheat.
 The reduced endosperm is known as flour (white flour) and the germ, bran and residual
endosperm obtained as by-products are used primarily in animal feeding.
 Flour milling is achieved by grinding in roller mills. Grinding is carried out in four or
five stages, i.e., in a gradual reduction process. Each grinding stage gives a "grind"
consisting of a mixture of coarse, medium and fine particles, including a proportion of
flour. The diffterent-sized particles are sorted by sifting and the coarse particles are
conveyed to a subsequent grinding stage. In each grinding stage, endosperm is separated
from the bran coats. The coarse fraction from the last grind can yield no more endosperm
and forms the by-product "bran." The percentage of wheat converted into flour from the
first grind to the fourth grind will be approximately 30, 66, 78 and 81.
 In India, a number of modern roller mills are working in different parts of the country. In
1981, there were 306 roller flour mills in the country and they produced 3.1 million tonnes
of wheat products during the year.
 Wheat is generally ground into atta (whole meal), suji or rava (semolina) and maida
(flour). Within these broad grades, there are finer divisions like high gluten and low gluten
atta, and low gluten, medium gluten and high gluten maida.
 Specifications for ground products are prescribed by the Indian Standards Institution (ISI)
which are given in below Table.
 In other countries, specifications have been worked for flours suited for particular
applications like bread, biscuits, cakes, etc.
 Recent developments in milling consist of fine grinding and air classification of flour
particles to yield fractions with different protein contents. This is known as "protein

4. displacement milling." This technique provides a means of obtaining from the flour of
a given wheat various fractions markedly different in protein content and, therefore,
suitable for different uses.
 It is possible to get from soft wheat (protein 10 per cent) a fraction containing 20 per
cent protein. Similarly, a fraction containing 30 per cent protein can be obtained from
hard wheat.
 By combining various fractions obtained by air separation, it is possible to obtain
flours of any desired specification from one parent flour.
(3.1) Nutritive value: Wheat provides in addition to energy (calories), considerable
quantities (20 per cent) of the human requirements of proteins, vitamins, calcium and iron.
The nutritive value of 100 per cent wholemeal (atta) is the same as that of wheat. Because
of preference for white bread, white flour (maida) having decreased protein, vitamins and
mineral contents is being produced by roller mills. In the case of commercial Indian flours,
the percentage decrease in protein content is about 4; lysine, 36.3; thiamine 49.5;
riboflavin, 71.7 and nicotinic acid, 67.0. There is also a decrease of more than 50 per cent
in the calcium, total phosphorus, phytin phosphorus and iron contents. The nutritional
deficiency of milled wheat flour is made good by supplementation, fortification and
enrichment. Wheat germ contains a high proportion of proteins of balanced amino acid
composition. Supplementation of wheat flour with 10-15 per cent defatted germ flour
brings about a striking improvement in the nutritive value. Addition of lysine, minerals
and vitamins increases the nutritional value of the wheat flour. Wheat powder/flour –
'whole grain' (mixture of germ, endosperm and bran)
 Atta flour – mixture of endosperm and bran
 Maida flour – endosperm, bleached; a very white flour, similar to the American
bleached flour
 Sooji/rava – coarse-ground endosperm
(3.2) Turbomilling and Air classification
 Further processing can separate flour into higher protein or higher starch fractions in a
process known as turbomilling.
 In turbomilling, flour from conventional milling is further reduced in particle size in
special high speed turbo grinders, which cause the endosperm agglomerates to abrade
against each other in high speed air vortex. The resulting protein and starch particles are
too close in size to be separated by sieves; they do differ sufficiently in particle size, shape
and density to separable in a stream of turbulent air.
 In this case the slightly finer protein particles rise and the starch particles settle in the
stream of air. The flour and air mixture is blown into a specially designed air classifier,
which then may possess centrifugal force on the suspended particles and two fractions of
flour differing in protein and starch concentrations are removed.
 Turbomilling make it feasible to custom blend flours for bread making, cake making,
cookies making and many other specific application.
(4) Milling of durum wheat
Milling durum wheat is different from conventional flour milling. The primary finished
product is semolina, not flour.

5. Fig. Flow-chart of durum wheat milling process
(5) Wheat products
(5.1) Indian wheat flour
 Wheat flour, and to some extent barley flour, have been used from prehistoric times in all
civilizations for the preparation of unleavened breads, probably much like the modern
Indian chapaties.
 Wheat flour when mixed with an appropriate amount of water forms a dough which is
elastic. The elastic substance is called gluten. Because of its gluten forming property,
wheat flour is used in the preparation of baked products, such as breads (yeast breads),
quick breads, cakes, pastries, etc.
 Gluten formation of wheat flour is due to the wheat proteins. It is the result of a complex
formed between gliadin and glutenin when flour and water are worked together during
dough formation. Neither glutenin nor gliadin have the ability to form gluten alone. Each
of these proteins have their own tertiary structure due to various types of bonds, including
the disulphide (S-S) bonds. During dough formation, the disulphide bonds are cleaved to
sulphydryl bonds (-SH) by the reducing agents present in flour and new disulphide bonds
are formed by the oxidizing agents, linking together separate molecules resulting in gluten
formation.
 Depending upon the nature of the baked product, different types of flour are milled. The
milling of whole wheat flour, white flour and enriched flours.
 Indian flours are generally categorized by how much of the grain is stripped away. Wheat
flours obtained at different stages of the gradual reduction process differ in terms of the
proportion of the endosperm, germ and bran contained in it.
(5.1.1) Assessment of Flour quality and characteristics
 It also depends upon the region of the wheat from which the endosperm is obtained.
 Thus, wheat flours differ widely in baking quality, colour, size, fibre and ash content and
nutritive value. The flour is known as "strong" if it has a high gluten content, and "soft" if
the gluten content is low.
 Strong flour (also known as "hard flour" or "bread flour"), being high in gluten, forms a
certain toughness that holds its shape well once baked.

6.  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.
 All-purpose flour is a blended wheat flour with an intermediate gluten level which is
marketed as an acceptable compromise for most household baking needs.
 In other words, the quality of each machine flour is distinctive and flour streams from
different machines can be blended to obtain flours of desired quality.
(5.1.2) Some of the other types or grade of flours made for baking are the following:
Bread Flour
 Bread flour should form good gluten when mixed with water and form bread with a good
volume when baked. Thus, bread flours should have a high protein content. They are
milled from blends of hard winter and spring wheats, and their moisture content, protein
content, ash content, starch quality, protein quality and particle size are all controlled.
Self-Raising Flour
 This flour is used domestically for making puddings, cakes, pastries, etc. This is made
from milling weak wheats of low protein content. Hard wheat up to 20 per cent can also be
used. The moisture content of the flour should not exceed 13.5 per cent in order to prevent
premature reaction between the chemicals present in the flour. The flour contains
leavening agents, alkaline and acidic substances which react and evolve carbon dioxide
during dough formation. Sodium bicarbonate and acid calcium phosphate or some other
acid ingredients are the chemicals used in the ratio of 1.16 per cent bicarbonate and 1.61
per cent acid calcium phosphate on flour weight.
All-Purpose Flour
 All-purpose flour (household or family flour) is made from hard wheat or a blend of hard
and soft wheats and has a moderate protein content. It does not contain self-raising agents.
It is suitable for use in yeast and quick breads, biscuits, pastries and cakes. A variation of
this flour is "instantized flour." This is instant blending flour. This is made by a special
agglomerating procedure whereby a number of individual flour particles are combined into
readily pourable particles.
Biscuit Flour
 Biscuit flour is made from weak wheats of low protein content. Depending on the type of
biscuit, special types of flours are made. The flour should make a dough having more
extensibility, but less spring (resistance) than bread dough. Dough pieces should retain
their size and shape after being stamped out.
Cake Flour
 Cake flour is a medium-strength flour ground from soft low-protein wheat of low a-
amylase activity and is very fine in structure. The purpose of flour in cakes is to allow an
aerated structure to be retained after the cake has been built up.
Enriched Flour
 Enriched flour is flour with nutrients added to it. According to the FDA, a pound of
enriched flour must have the following quantities of nutrients to qualify: 2.9 milligrams of
thiamin, 1.8 milligrams of riboflavin, 24 milligrams of niacin, 0.7 milligrams of folic acid,

7. and 20 milligrams of iron. Calcium may also be added at a minimum of 960 milligrams
per pound.
(5.2) Pasta
 It is a type of food made from the flour of various grains, water, and sometimes eggs,
which are mixed, kneaded and formed into various shapes, and boiled prior to
consumption. While the name comes from Italy, pasta is very popular all over the world.
The English word pasta generally refers to noodles and other food products made from a
flour and water paste, often including egg and salt. Less frequently, the term maccheroni is
used for the same products, especially when in combination with cheese. Dried Italian-
style pasta is made from durum wheat semolina, which gives it a light yellow colour and a
slightly chewy texture when properly prepared. Certain American pastas are produced
from a mixture of Farina and Semolina. Such pastas often have an inferior texture and
flavor and are only usable in a casserole or other dish where texture is less important.
Pasta is made either by extrusion, where the ingredients are forced through holes in a plate
known as a die, or by lamination, in which dough is kneaded, folded, rolled to thickness,
then cut by slitters. Fresh pasta cooks quickly and has a delicate taste, but spoils quickly
due to its high water content. Dry pasta generally contains about 10% moisture, which
makes it shelf stable for about three years.
(5.3) Macaroni
 It is typically machine-made dry commercial pasta, used in contrast to fresh pasta made at
home or in small local businesses. Macaroni technically must not contain eggs. Although
usually commercially made, some more advanced home machines do allow for the fresh
creation of macaroni pasta. Macaroni is a corruption of the Italian word maccherone and
its plural maccheroni. Thomas Jefferson is credited with introducing the first macaroni
machine in the United States, in 1789, when he returned home after serving as ambassador
to France.
 Macaroni products: Macaroni products are the class of food each of which is prepared by
drying formed units of dough made from semolina, durum flour, farina, flour, or any
combination of two or more of these, with water and with or without one or more of the
optional ingredients.
 The finished macaroni product contains not less than 87% of total solids.
 Macaroni is the macaroni product the units of which are tube-shaped and more than
0.11 inch but not more than 0.27 inch in diameter.
 Spaghetti is the macaroni product the units of which are tube-shaped or cord-shaped
(not tubular) and more than 0.06 inch but not more than 0.11 inch in diameter.
(5.4) Semolina
 Semolina is coarsely ground grain, usually wheat, with particles mostly between 0.25 and
0.75 mm in diameter.
 The same milling grade is sometimes called Farina, or grits if made from maize.
 It refers to two very different products: semolina for porridge is usually steel-cut soft
common wheat whereas "durum semolina" used for pasta or gnocchi is coarsely ground
from either durum wheat or other hard wheat, usually the latter because it costs less to
grow.

8.  Non-durum semolina porridge or farina has come to be known in the United States by the
trade name Cream of Wheat. Semolina pudding is made by boiling or baking the grain
with milk and sweeteners. The pudding can be flavoured with vanilla, served with jam,
and eaten hot or cold. In Italy (Tuscany) spaghetti made with semolina are called pici.
 In most of India, it is known as sooji; in Southern India, rava. In much of North Africa and
the Middle-East, it is made into the staple couscous. In Turkey "irmik helvasi" (halva of
semolina), made with semolina scorched with sugar, butter, milk and pine nut, is a very
popular traditional dessert which is made especially after funeral ceremonies. It can be
used as an alternative to corn meal to "flour" the underside of fresh pizza dough to prevent
it from sticking to the peel.
(5.5) Wheat beer
 It is a beer that is brewed with a significant proportion of malted wheat. It is common for
wheat beers to also contain malted barley. The addition of wheat lends wheat beers a light
flavour and pale colour. Wheat beers are brewed using both ale and lager brewing
techniques. The two most common varieties of wheat beer are Belgian Witbier and
German Weizenbier. Wheat gluten: also called seitan (pronounced SAY-tahn), wheat
meat, wheat-meat, wheatmeat, gluten meat, or simply gluten, is a foodstuff made from the
gluten of wheat.
 It is made by washing dough made from wheat flour in water until the starch is rinsed
away, leaving only the gluten, which can then be cooked and processed in various ways.
Wheat gluten, although not as well known, is an alternative to soy-based meat substitutes
such as tofu; some types may taste even more like meat than tofu due to their chewy
and/or stringy texture.
(5.6) Wheat Bran Flakes
 It is a breakfast cereal contains 100% of the United States Recommended Dietary
Allowance of eleven vitamins and minerals, including vitamins Bl, B3, B5, B6, B12, C, E,
and Iron, Riboflavin, Folic Acid, and Zinc.
(5.7) Wheat bread
 Bread is a popular food in Western and most other societies except for the Asian societies
that typically prefer rice. It is often made from 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.
(6) Important terms for manufacturing of bread
(6.1) Bleaching
 Flour contains a yellow pigment (xanthophyll) which is not desired in the making of white
bread. When the flour is exposed to air the colour of the flour is bleached by oxidation.
When the flour is stored in bulk this change is slow. The bleaching process is accelerated

9. by treating the flour with chemicals. The chemical additives are used for bleaching flours
used only for bread, biscuits or cakes and not for wholemeal atta used for making chapati.
 The chemicals used for bleaching include chlorine, chlorine dioxide, benzoyl peroxide and
acetone peroxide.
(6.2) Maturing
 The bread making quality of freshly milled flour improves with storage for 1-2 months.
The change occurs more rapidly if the flour is exposed to the action of air. During such
aerated storage enzymatic changes occur. Fats are first hydrolyzed by Upases to fatty acids
which are then oxidized by lipoxygenase. Due to the action of reductases, disulphide
bonds decrease in number and sulphydryl groups increase. These changes are known as
maturation or "ageing."
 Like bleaching, chemical substances or "improvers" accelerate maturation. Bleaching
agents, like chlorine dioxide and chlorine both bleach and act as improvers. Other
improvers used are potassium bromate, potassium persulphate, ascorbic acid,
azodicarbonamide (ADA) and L-cysteine hydrochloride.
(6.3) Leavening Agents
(6.3.1) Air
 Air is a leavening agent present in all batters and doughs. To some extent all baked
products—yeast breads, quick breads, cakes and biscuits—depend on air leavening. Air is
responsible for only a small portion of the total increase in volume of the finished product
but is important, because the effectiveness of water vapour as a leavening agent depends
on the presence of air in the batter and dough.
 Air incorporated through the mixing of the dough ingredients expands when the mix is
warmed in the oven and causes an increase in the volume of the baked product.
 The amount of air contained in batters depends upon the extent of mixing of batters, the
viscosity of the batter, the volume of ingredients, and the length of time elapsing before
baking.
 When extensive creaming of fat and sugar is employed as in the preparation of cakes, a
fat-sugar-air foam is formed making tiny air pockets.
 Some ingredients influence the amount of air held in batters and doughs. For example,
mixes containing egg-white have more air than those with egg-yolk or whole egg.
(6.3.2) Steam
 Steam, like air, is an ever present leavening agent. Even a small amount of water in a
batter or dough causes an appreciable leavening action as water expands (1,600 times)
when converted to steam during baking. Steam alone cannot leaven a mixture. Its action
must be combined with that of air and/or carbon dioxide.
(6.3.3) Chemical Leavening Agents
 The principal means of leavening flour mixes is by carbon dioxide, which is generated by
the action of chemical leaveners or by the action of micro-organisms on sugars.
 The most important chemical agent used in leavening is baking powder.
 Baking soda and acid ingredients, and sometimes ammonium carbonate, are also used
as leavening agents.
Baking powder

10. It consists of sodium bicarbonate (soda) and an acid component, which may be single or in
combination with another acid. The baking powders are named after the acid ingredient used
in the powder, as tartrate powder, phosphate powder and combination powder.
Baking powder also contains inert filler, which is commonly corn starch. The starch serves
two purposes. It acts as a buffer between soda and the acid and prevents their going into
action, when exposed to air, by absorbing moisture.
 Baking powder yields 12-14 per cent of available carbon dioxide.
 Sometimes powdered and dried egg albumen is added to the baking powders. It dissolves
in cold water and increases the viscosity of the dough which helps to hold gas bubbles in
the dough, thus increasing the effectiveness of the baking powder.
(6.4) Yeast
 A biological method of leavening is by yeast fermentation. Yeast is a unicellular micro-
organism that reproduces rapidly in the presence of sugars under appropriate conditions of
pH (4-6) and temperature (30°C). During the growth and multiplication of yeast, the sugar
decomposes into alcohol and carbon dioxide. This change takes place anaerobically and is
known as fermentation. There are many strains of yeast that bring about fermentation. The
particular strain of yeast used in baked products is Sacharomyces cerevisiae.
 A large number of reactions take place leading to the production of the final products and
the overall reaction can be represented thus:
 The carbon dioxide liberated during fermentation in the flour mixture leavens batters and
doughs, and the alcohol produced is driven off during the baking process.
 Flour contains about 1.5 per cent sugar on a dry weight basis. Sucrose is normally added
to yeast doughs. Yeast contains a number of enzymes that act upon carbohydrates.
Invertase of yeast hydrolyzes sucrose to glucose and fructose, which are fermented.
 Yeast used for leavening is marketed in two forms:
(1) Compressed yeast and
(2) Active dry yeast
(6.4.1) Compressed yeast: Properly selected yeast strains are grown in a medium of
molasses containing the necessary nutrients under controlled conditions. When growth
ceases, yeast cells are separated by centrifugation, mixed with a small amount of starch, and
compressed into cakes. Compressed yeast has a moisture content of 72 per cent and is the
most active form of yeast for bread making, but is unstable at room temperature. It must be
stored at 1° to 3 °C and even at this temperature it is active only for about five weeks.
(6.4.2) Active dry yeast: It is propagated in the same way as compressed yeast using special
strains of S. cerevisiae. It is then recovered, compressed, extruded and dehydrated at
approximately 43°C to about 8 per cent moisture. The dried material is then ground into
granular active dry yeast. The shelf life of dry yeast is over two years, if stored at 5°C and six
months when held at 32°C.