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INTRODUCTION

AYUB AGRICULTURE RESEAERCH

INSTITUTE, FAISALABAD
Ayub Agri. Research institute came with beings in 1962. When Agri. College and
research was upgraded and split into university and a separate research institutes. It has
since undergone several development stages adding new sections or institutes and
strengthening the old once.
Ayub Agriculture Research Institute (AARI), Faisalabad is the one of the most
prestigious organization of the country. Its mandate is the development of the technology
for food security, generation of exportable surplus, value addition and conservation of
natural resources. AARI originated in 1962 (after bifecturation of research and education)
is a successor originated of former Punjab Agriculture College and Research Institute
Lyallpur (Established in 1906).
AARI is the seat of green revolution which later spread to neighboring countries.
The momentum of green revolution has been kept by the release of more than fifty (50)
Wheat verities. Due to concreted breeding effort, no epidemic of rust could suffer after
1977-78. The currently popular variety in Pakistan, namely, Inqilab-91 is the best spring
wheat variety in the world, which is still the most favorite ever after 15 years, due to its
versatility

AARI has the capacity to meet the challenges of the 21 st century provided it receives
same level play field as UAF, NIAB, NIBGE and R&D organization of the country. New
crop varieties and their production technology alone will not lead to agriculture growth.
The full end beneficial efforts of agriculture research and technological advancement will
materialize only if government policies are appropriate and scientists are given the
package and status they deserve

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OBJECTIVES OF AARI

 Genetic improvement of the field and horticulture crops

 Production technology for yield maximization
 Introduction of new crop practices for improving / enhance economy.
 Development of crop protection technology
 Processing and preservation to avoid losses and stabilization
 Linkage with farmers and extension work

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ORGANIZATIONALCHART
OF RESEARCH WING

Minister Agriculture

Secretary Agriculture

Director General Agriculture (Research)

Director Mono crop Regional Discipline/Subject Discipline/Subject

Agriculture Commodity Research Wise Research Wise Research
(Research) Research Directories Directories Sections
Directories

Deputy Wheat Barani Agronomy Soil Chemistry

Director Cotton Post Harvest Soil Bacteriology

Research Sugar Cane Plant Protection Bio-Chemistry

In charge Vegetables Regional Rapid Soil Fertility Food Technology

Technical Oil Seed Soil Salinity Agri.Economics

Branch Pulses Soil & Water Statistics

Assistant Horticulture Arid Zone Conservation Bee keeping &

Research Orange Entomology Hill Fruits

Officer Maize & Millets Biotechnology

Fodder Plant Pathology

Rice

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WHEAT RESEARCH INSTITUTE

Wheat is a staple food crop and linchpin of food security of the country. The prime
objective of wheat research institute, Faisalabad is to develop wheat, durum and barley
varieties of high yielding, disease resistant and tolerant to Abiotic stresses with good
quality.
This institute has developed a stream of varieties, which improved wheat yield
over the decades. It continuously is looking forward into new canvass to synchronize its
goal or destination and, at the same time, to refine, and make up the existing practices for
improving farmers yield. The research is progressively going on wheat, durum, and
barley breeding, wheat agronomy, wheat pathology and entomology and wheat quality at
this institute.

SIGNIFICANT ACHIEVEMENTS
The most remarkable achievement of this institute was development of
 Mexi-Pak.
 Pak-81
 Inqlab 91
Not only revolution the wheat research work in Pakistan but it spread to many countries
of the world. It has been reported that during 1976 about 60 percent of high yielding
spring wheat of the world was derived from the same cross from which Mexi-Pak was
originated. While, Inqalab is the most widely cultivated wheat variety throughout the
world. Apart from this, more than 50 wheat durum and barley varieties were evolved
from this institute. The pipeline varieties includes
V-01078, V-02019, V-02156, V-03158 V-03079.

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EQUIPMENTS
IN
CEREAL TECHNOLOGY
LABORATORY

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THE ORIGIN OF WHEAT

Wheat shell be the grain of common wheat, club wheat and durum wheat, which before

the removal of dockage, consists of 50% or more of one or more of these wheats and not

more than 10% of other grains for which standards have been established under the

United States Grain Standards act and which after the removal of dockage contains 50%

or more of these kernels.

The origin of the wheat plant is not known with certainty, although a good deal of

evidence-indicates that cultivated einkorn was developed from the type of a wild grass

native to the arid lands of Asia Minor. Emmer is generally regarded as one of the

ancestors of the wheats common today, because it closely resembles the wild species of

the wheat found in the mountainous regions of Syria and Palestine. Crude wheat-type

plants such as einkorn and emmer and many wild species of grass are common to the

same area: therefore, Percival concluded that bread wheat originated by hybridization

from an emmer type and wild species of grass.

Authorities do not agree the exact place and time of the origin and earliest

cultivation of wheat, but it is well established that the Mediterranean region, centuries

before recorded history, various species of wheat played a major role in feeding the

population. After a period of low progress, wheat became commonly regarded as the best

of the cereal foods and the availability of the wheat for food was considered a sign of a

high stage of cultivation

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.

WHEAT FLOUR

Wheat flour is unique among the cereal flours in that when mixed with water in correct
proportions the protein will form an elastic dough which is capable of holding gas and
which will set to a spongy structure when heated in the oven. It is this phenomenon
which makes possible the production of wheat bread.
The peculiar properties of doughs made from wheat flour were explained by Halton and
Scott-Blair (1937.). They described flour dough as'containing protein chains which
behave like "coiled springs" and which are responsible for its elastic behavior. The
linkages between the chains are not equally strong at all points so that when the dough is
extended some of them break almost immediately causing permanent deformation of
flow, while others remain intact and maintain the rigid structure of the dough. "All of
these adjustments in the protein network have to take place in the presence of a starch-
water mixture which, although primarily fluid, also possesses some rigid properties, thus
complicating the situation, making impossible the complete relaxation of even those
protein units which are capable of truly elastic recovery.
Swanson (1938A) explained the phenomenon of gluten formation in wheat flour doughs
as related to the hydration of the gluten molecules. When flour is first wetted with water,
the protein particles are arranged in a heterogeneous fashion. ' The action of the mixers
tends to orient the gluten particles in a parallel arrangement. Where there is a pulling
action on the dough as in the case of commercial high-speed mixers or. in a recording
mixer, the protein strands become arranged into a more-or-less parallel position. When
this point is reached the dough acquires a smoothness which indicates to the baker that
the extent of mixing is adequate (Fig. 1). At this stage of mixing, the dough exhibits
maximum resistance to pull and the greatest degree of elasticity because the greatest
number of gluten coils or springs are in a position to resist elongation on the one hand
and to 'straighten back after elongation' on the other. Mixing beyond this stage breaks
down the dough causing it to become soft and sticky. If the dough has not been too

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greatly over-mixed, it will recover its strength if allowed to rest. These observations are
said to be due to each gluten filament being surrounded by a water film as a result of
over-mixing. Such over-mixed doughs will stick to surfaces through this water film
because the forces which hold these filaments together are the same forces which attract
the water to other surfaces. Doughs from different flours require different amounts of
mixing to develop them to a satisfactory degree. This is. explained by differences in the
rates at which the water in the dough combines with, or hydrates,' the gluten. There may
also be differences in the configuration of molecular structure and the way in which the
protein particles are bound together in the gluten strands.
Baker and Mize (1941) studied the origin of gas cells in the doughs and
considered five hypothetical sources of gas cells as follows: (1) the gas cells in
the .endosperm particles are incorporated in the dough; (2) the gas voids between the
endosperm particles are incorporated in the dough; (3) the mixing beats gas into the
dough and subdivides it to produce gas cells of small size; (4) the gas pressure caused by
the yeast will originate new cells around the organism; and (5) the work applied to the
dough after it is mixed, such as folding, punching, rolling, moulding, and twisting,
subdivides gas particles to increase their number.
Each hypothetical source of gas cells was considered further by studying a series
of doughs in vacuum. On the basis of this work it was concluded that the yeasts
themselves are -incapable of originating gas cells in doughs but furnish dissolved gas
which diffuses into cells formed from air beaten into doughs during the mixing operation.
Baker (1941) separated intact gas cells from dough as thin translucent protein bubbles by
diluting doughs with brine. The cell wall material was found to be glutinous in character
and to consist of about 45 per cent protein and 25 per cent starch on the dry basis.
From observations on fermenting doughs. Baker noted that there was a tendency
for the starch and gluten to separate during fermentation and for the gluten to form into
transparent cells. This led him to conclude that the starch in flour is not necessary for cell
formation in doughs. Baker further stated that "this film is drawn to the surface because
the gas nucleus from which the bubbles originated is a glutinous core. As the bubble was
expanding the required amount of gluten to satisfy its surface needs was drawn from the

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starch-gluten matrix of the endosperm material. The properties that enabled this to occur
may be controlled by the viscosity and fluidity of the gluten and the amount of adhesion
of the gluten to starch."
In the light of the above observations, the importance of intensive mixing of cake batter is
emphasized because vigorous mixing action will incorporate minute air bubbles into the
batter which can later expand during baking into the fine cells necessary for proper
texture in the finished cake. The quantity of gas necessary for expansion could come
from several sources, including chemical leavening used in the batter, from steam
developed during baking, or from the expansion of the occluded air bubbles themselves at
baking temperature.

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TYPES OF WHEAT

Commercial wheat varies widely in properties depending on the variety and area where
grown. They may be loosely grouped into two general headings as hard and soft. The
hard wheat includes hard spring, hard winter and durum.
The hard spring and hard winter wheat are the types most desirable for bread
production. They mill well and yield good quantities of flour that is high in good quality
protein, from which strong, elastic doughs can be made with proper development. These
doughs have good tolerance to bakeshop conditions with respect to mixing, fermentation,
temperature, etc., and have excellent gas-holding properties and will yield bread with
good volume, grain, and texture under a wide range of conditions. The hard wheat
doughs have high water-absorptive capacity and generally have excellent dought
handling properties when properly matured. The hard spring and hard winter wheat
comprise about 70 per cent of the annual acreage sown to wheat in the United States.
Durum wheat is produced principally in two varieties, amber durum which is
used chiefly in making alimentary pastes such as macaroni, spaghetti, noodles, etc.; and
red durum, which has very little value for milling and is used principally as a poultry and
livestock feed.
The soft wheats include soft red and soft white wheats grown principally in Ohio,
Missouri, Indiana, Illinois, Pennsylvania, New York, and Michigan, and the Pacific
Northwest. These wheats comprise about 20 per cent of the total acreage grown in the
United States and are used principally in the production of flour for cakes, pastries,
cookies, etc. They are characterized, for the most part, as being low in protein and they
yield flours which have low water-absorption capacity and poor tolerance to mixing and
fermentation in bake shop practice. They handle poorly in bread baking equipment. They

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are generally considered undesirable for commercial bread production but are highly
desirable for the production of cakes, pastries, and cookies.
Schellenberger and dark (1924) reported milling and baking results on a large
number of samples of several varieties. It will be seen that the hard red spring and winter
wheats rated highest in loaf volume, while the soft wheat rated lowest. The hard wheats
all rated higher in absorption than the soft wheats, with durum rating the highest.

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WHEAT
PRODUCTS

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PREPARATION OF CAKES

Ingredients for Cake Making (1 Pound)

Ghee 125g
Sugar 125g
Flour 125g
Egg 3-4
Baking powder 4g
Milk 20-25 ml.
Procedure:
1. In cake making process, first of all we blend the shortenings for about 8-10 min. so that
its grain size reduced in order to get the uniform creamy texture.
2. Then we grind the weighed sugar in grinder.
3. Now we take both the sugar and shortening in a pan and mix them thoroughly for
about 10 min. to incorporate the air so that both the sugar and ghee get the uniform cream
like consistency.
4. Add the egg one by one and mix them in the above mixture. More no. of eggs used in
cake making process.
5. After this add 20-25 ml milk
6. Dissolve the color in small quantity of water and add it in the mixture.
7. At the end we will add 4 g. of baking powder and flour and mix to form the batter.
8. Then fill the batter in pre-greased pan having paper lining on inner side.
9. Place them in oven having some moving arrangements for uniform baking at 176 oC
for 1 hr.
10. Slicing is done manually on cooling.

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CAKE SCORING
The great variety of commercially produced cakes makes a single scoring system
impossible to apply. Only general characteristics may be discussed, and the quality
control technologist must establish the points he feels are important to his company.
As in bread, scoring points may be divided into external and internal.
 External
The volume, or specific gravity, is of great importance, and the
volume of any sample to be scored must be checked against the norm established for that
variety.
The color of the crust is important. Thick, dark crusts are objectionable. Spotty
crust of non-uniform color is objectionable to the eye. In layer cakes especially, the
symmetry of form is important. The layers should be even and not have a high center, or
be depressed in the center. The crust should not be blistery, tough, rubbery, or dry.
 Internal
The crumb structure is important. The cells should be small with
thin cell walls. Stratification, especially in pound cakes, is to be avoided.
Crumb color is an important scoring characteristic. If the cake is a
yellow cake, the intensity of yellow color should be noted. Color is affected by crumb
structure, and a fine crumb will give the appearance of a lighter color.
Aroma and taste should be checked with very careful
consideration being given to foreign odors and tastes since cake is especially susceptible
to absorption of foreign odors and tastes.
A determination of total moisture is important since
this factor has considerable bearing on the shelf life of the product. The optimum mois-
ture must be established for each type of cake,

PACKAGING
Packaging is especially important in cake products, and it is useful to record the
type of wrapping material used as to whether, for example, it is regular Cellophane,
polymer-coated Cellophane, or other types of wrapping material.

ICINGS AND CREAMS

The stability of icings and creams is especially to be noted. Icing that dries
out and becomes crumbly, or conversely icings that become sticky are undesirable.

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Creams may break down and become watery without proper stabilization. In warm
weather, icings and creams must be watched for any possible development of bacterial
spoilage.

PREPARATION OF BISCUITS

Ingredients for Biscuits Making

These ingredients are required for making 4 Kg. biscuits
Flour 2 Kg
Ghee 1 Kg
Sugar 1 Kg
Egg 12
Baking powder 32g
Colour 2-3 g in water
Procedure;
1. In biscuit making process, first of all we blend the shortenings for about 8-10 min. so
that its grain size reduced in order to get the uniform creamy texture.
2. Then we grind the weighed sugar in grinder.
3. Now we take both the sugar and shortening in a pan and mix them thoroughly for
about 10 min. to incorporate the air so that both the sugar and ghee get the uniform cream
like consistency.
4. Add the egg one by one and mix them in the above mixture.
5. Dissolve the color in small quantity of water and add it in the mixture.
6. At the end we will add 32 g. of baking powder and flour (meda) and mix.
7. Then take the dough, mold it by hands and place it in molder by using different dies in
order to get the biscuits of different shapes.
8. Place them in pre-greased trays and place these trays in oven at 232 °C for 10-15
minutes.

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COOKIES EVALUATION SCORE CARD

Date: Name of the judge: ,

Characteristics
A. Physical
B. Sensory
A. Physical characteristics
Character T1 T2 T3

Thickness
Width
Spread factor = W/T x 10
B. Sensory characteristics
Character T1 T2 T3
Color
Flavour
Taste
Crispiness
Texture
Overall acceptability
INSTRUCTIONS
Chew a sample of biscuit and score for the above mentioned sensory characteristics using
the following scale
Extremely poor ……………………………1
Very poor………………………………….2
Poor……………………………………….3
Below fair above poor…………………….4
Fair……………………………………..…5
Above fair below good……………………6
Good………………………………………7
Very good…………………………………8
Excellent…………………………………..9
Before evaluating each sample, rinse mouth with distilled water

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Make inter comparison of the samples and record the score.

STRUCTURE
&
COMPOSITION
OF
WHEAT GRAIN

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STRUCTURE OF WHEAT GRAIN

Wheat grain consists of three main parts.

1. The germ or embryo 2%
2. Starchy endosperm 85%
3. Husk 13%

 The germ or the embryo (including its sheath, the scutellum) that produces the
new plant.
 The starchy endosperm that provides the food for the new plant when the embryo
first starts to grow or is the source of the flour.
 The various outer coverings constituting the husk of the grain that are for the
protection.
 Husks contains a number of distinctive parts B The pericarp, mesocarp, and
endocarp. These represent 4 % of the grain.
 The testa or seed coat that contains the pigment gives the grain the particular color
and comprises 1-2 % of the grain.
 The nucellar layer that protects the endosperm from the effects of moisture. This
layer and testa together represent about 2-3 % of the grain.
 The aleurone cell layer that consisting of square, heavy walled cells and
containing the proteins. The aleurone cell constitute about 6-7 % of the grain.

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COMPOSITION OF WHEAT

Approximate composition of wheat

Moisture 9-18%
Starch 60-68%
Protein 8-15%
Cellulose 2-2.5%
Fat 1.5-2%
Sugar 2-3%
Ash 1.5-2%

Composition of endosperm, germ and bran (commercial samples)

Components Endosperm Germ Bran

Moisture 14% 11.7% 13.2%
Protein 9.6% 28.5% 14.4%
Fat 1.4% 10.4% 4.7%
Ash 0.75 4.5% 6.3%
Carbohydrate 74.3% 44.9% 61.4%
Starch 71.0% 14.0% 8.6%
Hemi cellulose 1.8% 6.8% 26.2%
Sugars 1.1% 16.2% 4.6%
Cellulose 0.2% 7.5% 21.4%
Total CHO 74.1% 44.5% 60.8%
Recovery of fraction 99.8% 99.6% 99.7%

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WHEAT QUALITY

HOW THE WHEAT QUALITY IS DEFINED

In general wheat quality is suitability for specific product. If it is suitable for
specific product than it posses good quality, if not suitable than of poor quality.
Different individual have different criteria for quality.
For example;
 Farmer point of view, the wheat which posses more grain yields that is of better
quality.
 Miller main quality criteria is less impurities, ease in processing, less power
consumption, high flour yield.
 Baker wants wheat which have higher water absorption, good loaf value, and
product soft, less mixing time.
Wheat quality is of necessity closely related to the quality of its milled products. Criteria
of quality involving evaluation or testing of wheat itself either the whole or ground state.
Most of these evaluations, of course, are used to predict the quality or quantity of the
flour or other milled products derived from the wheat

CRITERIA OF WHEAT QUALITY

There are three main criteria's of wheat quality

 Botanical criteria of quality
 Physical criteria of quality
 Chemical criteria of quality
BOTANICAL CRITERIA OF QUALITY
SPECIES
Of the 15 species of wheat, only three are of any commercial importance in
1. Triticum aestivum..........42 chromosomes
2. Triticum compactum.......42 chromosomes

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3. Triticum durum.............28 chromosomes
1. Triticum aestivum (Common wheat)
Triticum aestivum is the most widely cultivated of all wheat species and
constitutes about 93% of the wheat produced. The most outstanding characteristic of this
species from a stand point of economic value is that, its flour is superior to that of all
other species for the production of leavened bread.
2. Triticum Durum (Durum Wheat)
Although it is very occasionally included in small proportions in bred
grists, it is mainly converted into semolina
3. Triticum compactum (Club wheat)
Its flour is suitable for the manufacture of confectionary and biscuits.

PHYSICAL CRITERIA OF QUALITY

Depends upon the following parameters:
a. Weight per unit volume/Test weight
b. Kernel weight:
c. Kernel size and shape
d. Kernel hardness
e. Vitreousness
f. Color
g. Impurities
h. Milling quality

CHEMICAL CRITERIA OF QUALITY

A. MOISTURE CONTENT
Moisture content is one of the most important factors affecting the quality
of wheat. Since the amount of dry matter in wheat is inversely related to the amount of
moisture it contains, moisture content is of direct economic importance. A carload of
wheat of 14% moisture content contains about 2,800 gallons of water.

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Of even greater significance in the effect of moisture on the keeping quality of wheat.
Dry, round wheat can be kept for years if properly stored, but wet wheat may spoil
completely within a few days. It is not possible however, to •set precise moisture limits
for the safe storage of wheat or to predict accurately how rapidly it will deteriorate at any
given moisture content, because various factors other than moisture have marked effects
on storage behavior. Near the critical moisture level small differences in moisture content
make relatively large differences in keeping quality.
Wheat that is too dry also has some advantages. Very dry wheat tends to be brittle
and to break easily in commercial handling operations. This is particularly true when
wheat is artificially dried. Although in artificial drying operations no attempt as usually
made to reduce the average moisture content below about 13%, some of the wheat of
each batch dried is likely to become much dried because of tendency of the dryers to dry
unevenly. It is the very dry kernels that break easily.
Broken kernels are of little milling value, since most of them removed in cleaning
operations. Another disadvantage of very dry wheat is that it is sometimes more difficult
to temper it properly to the moisture level required for milling. Under the U.S. Standards,
wheat that contains more than 13.5% moisture is graded "tough." This is the moisture
limit below which wheat is usually considered safe for limited period of storage,
particularly at high temperatures; considerably lower moisture content is required to
ensure the safe keeping.

DETERMINATION OF MOISTURE CONTENT

1. Oven Drying Method

The basic method for determining moisture in wheat is usually considered
to be the 130°C. 1-hr. air-oven method. Results obtained by this method are close with
Karl Fischer method which is most accurate method.

Preparation of the Sample:

The objective of preparing is to obtain a representative sample that is to be

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analyzed. It must represent the part or portion required for the purpose. Cereal grains and
legumes are ground to powder form.

Procedure:
1. Weigh an empty flat-bottomed dish.
2. Place the sample in the weighed dish.
3. Weigh the dish with the sample
4. Place the dish in an oven at 100°C.
5. Remove the dish after 4 hours, cool in a dessicator and weight.
6. Place the dish again in the oven for another two hours and weight again.
7. Repeat again till constant reading is obtained.

Calculations:
Wt. of fresh sample - Wt. of sample after drying
Moisture (%)= X 100
Wt. of sample

2. Moistures Meters
Moisture meters are also available. These meters are of greater physical value,
particularly in routine inspection work, because with them moisture determination can be
made very quickly.

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B. PROTEIN CONTENT
Protein content in wheat varies from about 6% up to about 20% depending
in part on variety and class but more largely on environmental factors during growth.
Abundant rainfall during the period of wheat development usually results in low protein
content, where as dry conditions during that period favor high protein content. Protein
content is also influenced considerably by the available soil nitrogen. Heavy nitrogen
fertilization increases the protein content of wheat. Finney et al. have shown that protein
content can be greatly increased by spraying wheat in the field with urea at appropriate
times during kernel development
For the production of yeast-leavened bread, flour with a protein content of at least 11 %
is usually preferred. To produce such flour the wheat must have a protein content of at
least 12%. In many countries climatic conditions make it impossible to produce wheat of
that protein content level and as a result these countries usually import wheat of high
protein content to blend with their local wheat. Protein content of wheat is ordinarily
determined by the well-established Kjeldahl Procedure. This method is quite precise
and subject to very good reproducibility within and among laboratories when careful
attention is paid to all details of the procedure.

PROTEIN QUALITY

Wheat proteins, particularly those of the endosperm, are deficient in some of amino acids
essential in animal and human nutrition. Diets in which wheat or other grain products
supply the major part of the protein and which contain no substantial quantities of animal
products are likely to be deficient in lysine, threonine, and methionine, lysine being the
most deficient. Lawrence et al. have shown that the lysine contents of wheat protein is
quite variable and the variation is largely a varietal characteristic, on the basis of these
findings they believe that it may be possible to increase the lysine content of wheat
significantly through breeding.
It is known that wheats of the same protein content will produce flours which behave
quite differently in baking operations, and that in many instances these differences are
attributable to qualitative difference; in the gluten proteins. Gluten quality is largely a
varietal characteristic, although it has been shown by Finney and Fryer that excessively
high temperature and low relative humidities during the period when wheat is maturing in

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the field may have a marked deleterious effect on the quality of gluten.

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TWO TESTS REFLECT DIFFERENCES IN GLUTEN QUALITY

1. The wheat-meal fermentation-time test or dough ball test.

2. Sedimentation test

1. THE WHEAT-MEAL FERMENTATION-TIME TEST

Whole-wheat meal is made into small dough balls with a yeast suspension
and the dough balls are immersed in water, maintained at a constant temperature. After a
time the dough balls disintegrate and the elapsed time between immersion and the
beginning of the disintegration is referred to as the "test number"
This time will vary from less than 30 minutes for very weak wheat to more than 400
minutes for the strongest wheat. The test number is influenced both by the quantity and
the quality of the gluten. By dividing the test number by the percentage of protein in the
wheat, a value is obtained that is an index of gluten quality alone. In some countries,
wheat-meal fermentation-time test is commonly referred to as the Pelshenke test. It is
used by plant breeders in some countries in Europe and in central South America.

2. SEDIMENTATION TEST
Coarsely ground wheat is sifted to remove most of the bran and a weighed
portion of the crude white flour is suspended in H2O and treated with lactic acid in a
graduated cylinder. The volume of the sediment, consisting principally of swollen gluten
and occluded starch, after a 5 minute standing period is the sedimentation value. Values
vary from about 3 for very weak wheat to 70 or more for very strong wheat. The
sedimentation value is also influenced both by the quantity and the quality of gluten,
Dividing the sedimentation value by the percentage of protein gives specific
sedimentation value that can be used as an index of gluten quality alone. Bread baking
strength can be estimated more closely from the sedimentation value than from specific
sedimentation value, since it is also influenced by both quantity and quality of gluten.

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DETERMINATION OF GLUTEN
HAND WASH METHOD

SCOPE:
APPLICABLE TO FLOUR AND SEMOLINA.
Procedure:
a. Weigh 25gm flour in to a cup
b. Add sufficient tap water (15ml) to form firm dough ball and work into dough
with spatula taking care that no material adheres to utensil.
c. Let dough stands in water at room temperature for about 1 hour.
d. Knead dough gently in stream of tap water over cloth until starch and all soluble
mater are removed.
e. This operation requires approximately 12 min. to determine weather or not
gluten is approximately starch free let or one or 2 drops of wash water obtained
by squeezing ball into beaker containing clear water if starch is present
cloudiness appears,
f. Let gluten thus obtained by washing stand in water 1 hr press as dry as possible
between the hands roll into a ball.
g. Place in weighed flat bottom dish and weigh as moist gluten.
h. Transfer to oven dry to constant weight at 100oC (24 hrs)
i. Cool in dessicator and weight as dry gluten.

Note: Crude gluten thus obtained is not pure protein but contains lipids, ash and
some starch.

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PROTEINS OF WHEAT

Amongst the many earliest workers on the proteins of wheat, the names of Osborne and
Voorhees stand prominent even though their work was published at the end of last
century. They suggested the existence of five reasonably distinct proteins in flour
namely:
1. Albumin.
2. Globulin.
3. Proteose.
4. Gliadin.
5. Glutenin.
The first three are comparatively unimportant and exist in wheat in only small quantities.
The albumin (0.3 percent approximately of wheat) and the globulin (0.6 %-0.7%) can be
extracted from flour by dilute salt solutions. The proteose (0.3%) may even be formed by
the degradation of other proteins present during the process of extraction.
Thus the gliadin and the Glutenin, the principle cereal proteins recognized by Osborne
were regarded as, together with water and salt, forming the well known substance gluten.
Gliadin is present in wheat to the extent of over 4 percent, (the total quantity depending
of course, on the amount of total proteins present), while normally the amount of
Glutenin is similar to that of gliadin.
Gliadin can be easily extracted from gluten by digestion with 70% alcohol. To form
gluten, both the gliadin and Glutenin are necessary. Glutenin is said to give solidity to the
gluten and the gliadin, which is soft sticky body is responsible for binding.
The proteins of wheat are not, however, distributed evenly throughout the whole grain, as
the bran and germ are richer in proteins than is the endosperm. It is the quality of the
gluten rather than the quantity of gluten that influences baking quality.
In cereal the factor 5.7 is normally used for converting the percentage of nitrogen into the
percentage of protein in flour and wheat.

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DETERMINATION OF NITROGEN AND PROTEIN

KJELDAHL METHOD
Reagents:
1. Sulfuric acid, approximately 96% H2SO4
2. Catalyst, polyethylene packets containing 15 g. potassium sulfate and 0.7 g. of
mercuric oxide and approximately 0.10 g. pumice.
3. Antibumping agent (pumice stone)
4. Conc. Sodium hydroxide NaOH (sol) or liquid NaOH already prepared.
5. Methyl red-methylene blue indicator.

Procedure:

1. Digestion
Weigh quickly and accurately 1g finely ground sample. Place in digestion flask
(sample may be placed in nitrogen free paper to prevent clinging to sides of flask.) Add
polyethylene packet of catalyst and conc. Sulfuric acid to flask. Digest till solution is
clear and then 30 minutes longer, remove and cool but don't allow to crystallize.

2. Dilution
Take the above solution and make the volume in 250 ml. flask up to the mark.

3. Distillation
Place 300 ml. bottle or flask containing 50 ml. boric acid methyl red-methylene
blue indicator solution under condenser tube with tip of condenser tube immersed under
surface of solution. Add to original flask, 250-300 ml.tapwater and anti bumping agent, if
not previously added. Gently add 50 ml. conc. NaOH, connect to condenser with tight
filling rubber stopper and swirl. Boil until all ammonia has distilled (at least 150 ml. of
distillate) and then set receiving bottle down so that condenser tube is completely
drained.

4. Titration
Titrate distillate to neutrality with standard 0.1N H2SO4, using burette. Read ml.
of acid used, directly from burette. Run blank sample. Periodically, using all the
ingredients except sample.

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Calculations:

% Protein = (ml. of H2SO4 X N of H2SO4) X 1.4007 x factor

Sample wt. (g)

Where factor for wheat, flour and bread = 5.7

For other grains = 6.25
For milk = 6.38
For unknown samples = 6.25

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C. FAT AND LIPIDS
Flour and other proteins of grains derived from wheat contain a small
portion of fat or oil, characteristic of wheat. Fats usually consists of compounds of
glycerol and fatty acids, each molecule of glycerol combining with three molecules of
various fatty acids such as oleic, stearic, palmitic, linoleic and linolenic etc.
Whole grain may contain from a little over 2 percent to rather under 4 percent of fatty
material. There is more oil in germ then in any other portion of the wheat grain.
Herd and Amos found patent flour to contain about 1 percent of fat, bran 3.5 % and
commercial germ, which is always contaminated with bran material, nearly 7 %.
Since there is so high a proportion of the unsaturated and the generally regarded
nutritionally important essentional fatty acids in flour. Sinclair has been critical of any
flour oxidation treatment that might destroy them. These essentional fatty acids represent
over 60 % of the total fatty acids in flour. The principle ones are the dienoichnoleic and
the trienoic and linolenic acids. Hilditch found that wheat germ oil contained the
following percentage of fatty acids.
Palmitic 13.8%
Stearic 1.0%
Oleic 30.0%
Linoleic 44.1%
Linoleinic 10.0%
FAT ACIDITY
As wheat and other grains deteriorate in storage, various chemical changes
occur. Under ideal storage conditions these changes progress very slowly, but when
conditions are unfavorable they progress rapidly, reflecting a rapid rate of deterioration.
Zeieny and coleman showed that of the various chemical changes studied which occur
during grain deterioration, the breakdown of fats by lipases with the liberation of free
fatty acids is the most rapid and begins during the earliest stage of deterioration. This led
to the development of a convenient fat for determining fat acidity have been developed
by Baker et al. and by Baker.
“Fat acidity is defined as the number of mg. of potassium hydroxide required to

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neutralize the free fatty acids from 100 g. of grain and calculated to a moisture free basis”

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D. CRUDE FIBER
Both the crude fiber and the ash content of wheat are related to the amount
of bran in the wheat and hence have rough inverse relationships to flour yield. Small or
shriveled kernels usually have more bran on a percentage basis and therefore more crude
fiber and ash, and yield less flour than large plump kernels. The crude fiber content of
wheat is usually within the range of 2.0 to 2.7% and the ash content within range of 1.4-
2.0% both are calculated on 14% moisture basis.

E. ASH
Determination of Ash
Ash contents represents the presence of inorganic residue remaining after the organic
matter has been incinerated.
Procedure:
1. Place the sample in weighed crucible and weigh.
2. Place the crucible on heat at 100 °C until water is expelled from the sample.
3. Then char the sample gently over low flame
4. Place the crucible in muffle furnace set at 525 °C and leaves until gray colour is
obtained.
5. Re-ash in muffle furnace at 525 °C to constant weight.

Calculations:
Ash (%) = Weight of sample after Ashing x 100
Weight of sample

F. ALPHA-AMYLASE ACTIVITY
Rainy weather after wheat has matured in the field but before it is actually
harvested may cause some of the kernels to sprout. Such kernels have a very high alpha-
amylase activity. Even if visible sprouting does not occur, the alpha-amylase level may
be considerably elevated as a result of wet harvest season.
Thus the alpha- amylase activity of wheat cannot be reliably estimated by determining

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the percentage of sprouted kernels. Malted wheat or barley flour is often blended in very
small quantities with flour milled from wheat of low alpha-amylase activity to bring this
activity up to the optimum level for bread dough fermentation.
Excessive alpha-amylase activity is a common problem in much European wheat because
of the frequent wet harvest seasons.

FALLING NUMBER TEST

Chemical methods for determining alpha-amylase activity have been described by

Hagberg and Perten. A "falling number" test also devised by Hagberg for measuring
alpha-amylase activity has proved to be more practical than the conventional chemical
methods. Falling number is the time in seconds, required to stir and allow a viscometer-
stirrer to fall a fixed distance through a hot aqueous flour suspension being liquefied by
the enzyme in a standardized apparatus.
Tipples have developed a viscometer method for measuring the alpha-amylase content of
very small samples. It can be applied to single wheat kernels and may prove valuable in
breeding work, since efforts are being made particularly in Europe, to develop wheat
varieties that resist sprouting during wet harvest season.

G. STARCH
Starch is the name of class of naturally occurring carbohydrates that are
found particularly in the nutrient reservoir of plants. Wheat starch, like most other
starches, contains two components known as amylose and amylopectin. Amylose which
constitutes about 23%. of the weight of the starch consists of straight un-branched chains
of glucose units linked by a -1:4 glucosidic bonds, while the amylopectin consists of
highly branched short glucose chains also linked by a-1:4 glucosidic bonds between the
branch points and at the branch points by a-l:3 and a-l:6 glucosidic bonds.
An important point is that these components react differently to enzymatic attack. The
enzyme a- amylase will convert the straight chain portion of the starch, the amylase, to
maltose but it is unable to attack amylopectin beyond the branch points. The enzyme a-

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amylase, however, can attack the linkages at the branch points and, once this has been
done, P-amylase can attack the free ends thus liberated. Hence when there is mainly a p-
amylase attack on amylose, the resulting product is maltose together with a residue from
the amylopectin portion, which is a complex dextrin of high molecular weight and which
incidentally strains purple with iodine. When a-amylase breaks down the starch, gummy
dextrin's of low molecular weight are formed from the attacked amylopectin and it is
there that are so harmful in bread, making the crumb clammy and sticky. These low
molecular weight dextrin's don't strain with iodine.
It should be remembered that bread making process allows only a limited time for the
amylase to attack starch. Moreover it would appear that only available or attackable
starch granules are concerned in sugar production in dough that is only the starch
granules that have been physically damaged in the grinding process. The bulk of the
starch is undamaged and in ordinary bread making process this is not attacked by amylase
and probably only very slightly by a-amylase. The amylose fraction is said to be slightly
soluble in water and gives with iodine the typical blue coloration while the complex
formed by the action of iodine on the much less soluble amylopectin has a more violet
color. Certain species of maize are known that contain particularly no amylose, that is
their starches are composed essentionally of amylopectin.They are known as the waxy
maize. Starches seen to be consists of granules, the shapes and ranges of size of which
vary with the type of the starch. Wheat starch consists of roundish granules of various
sizes. The diameter of these, granules is between 0.002mm-0.05mm.Starch granules are
enclosed within a sheath of cellulose-link materials.

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ENZYMES IN WHEAT FLOUR

Wheat and flour like the products of other living matter are not just inert substances but
contain active enzymes that affect, amongst other constituents, both proteins and starch.
Enzymes are a group of complex chemical substances, present in and essential to living
organisms or cells and, acting catalytically, are able to bring about pronounced changes
in spite of being present in only trace amounts. Enzymes, as a group, have certain
properties and these are well illustrated by those present in cereals and cereal products,
The most important enzymes in wheat are perhaps those that are collectively known as
diastatic enzymes. Their function is to break down some of the starch into sugar,
principally maltose. The diastatic enzymes are found chiefly in the embryo or germ of the
wheat, grain, but all flour contains a certain amount of these natural chemicals known as
enzymes.
Diastatic enzymes can be obtained by extracting malt with 20 per cent, alcohol,
the extraction continuing for 24 hours or more. Highly active preparations are
precipitated from the clear filtered extract by the addition of excess of absolute alcohol.
The two main components of the diastatic .group of enzymes are known as % amylase
and (i amylase. Broadly speaking, P amylase converts starch into maltose and a amylase
produces dextrin. The work of Blish, Sandstedt and Kneen 23 indicates that p amylase is
capable of acting on only the "available" starch in wheaten flour, i.e., the granules that
have been physically damaged during the milling process. Again, although a amylase can
attack undamaged or unbroken starch, little action on such starch even by a amylase is
likely to take place under the ordinary conditions in the bakery. The activity of these
diastatic enzymes, like that of other enzymes, is influenced by temperature and acidity.
The small amount of maltose originally present in flour (possibly made by the previous
action of the diastatic enzymes) and the other fermentable sugars are the materials which
the yeast first ferments in a dough. As these are being used up, the P amylase present in
the flour, under the influence of the water and heat and stimulated by the acidity
developed by the yeast, acts on the available. Starch and produces more maltose. The

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production of gas at the critical time of "proving", which is all-important, is due to the
action of the yeast on the maltose that has been formed by the a and p amylases during
the fermentation; the original ' sugars have, in the main, been used up by this time.
A flour with little diastatic activity will not take very much colour on the crust
when baked, so that the crust of the loaf "tends to have a pale or anaemic appearance.
Further, such flour may fail to produce in the dough, towards the final and important
stages of fermentation, sufficient gas and this may restrict the oven development and-
cause the production of a small and unsatisfactory loaf.
A certain amount of diastatic activity in flour is, therefore, not only desirable but
essential; excessive a amylase activity is, however, harmful as it causes stickiness in the
crumb of the loaf although sometimes, in moderation, it may be helpful in the case of
really very strong glutenous flours.
For the separation of  amylase from  amylase in diastatic preparations, heat and
acidity have been used. Nordh and Ohisson destroyed the maltose-producing agent (
amylase) by heating at 70°C. for fifteen minutes and the dextrin-producing agent (
amylase) can be checked by acid.
Wheaten flour contains many enzymes other than diastatic enzymes, while a
fermenting dough made with yeast contains still more. Amongst other enzymes found in
yeast, there are maltase, invertase, and a group once known as zymase. Maltase has the
specific action of hydrolysing the maltose, formed by diastatic activity, to dextrose.
Invertase is the enzyme that has the power of inverting or hydrolysing the cane sugar to
dextrose and laevulose. The zymase group is responsible for the fermentation of the
sugars, with the consequent production of carbon dioxide and alcohol. At the same time
traces of acids and glycerin are formed.
Although -perhaps the most important enzymes in flour are the diastatic izymes
that are called the amylolytic or starch-splitting enzymes, there also exist in flour
proteolytic enzymes. The name protease or proteinase has been given to these enzymes.
The action of proteinase is to split up the proteins into simpler bodies such as the
peptones, polypeptides, etc. The action of excessive proteinase on gluten is usually
injurious as the elastic qualities are impaired, and the gas-retaining power, in
consequence, is seriously diminished. Nevertheless, some proteolysis is required in

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panary fermentation, so that the gas may easily distend the dough'. This softening action,
which may be associated with what the baker calls the ripening of the dough, is thought
to be in part effected, by the proteases of the flour and partly by those of the yeast.
Possibly also the acids formed in fermentation assist but, without some proteolysis, the
dough might be too unyielding and dead.
The greater the length of extraction of the flour from the wheat, the greater is the
possibility of excessive proteolytic activity. Brown flour generally has a higher
proteolytic activity than white flour from the same wheat.
Investigations by various workers have suggested that flour contains certain substances
which serve as activators of the proteolytic enzymes and if the effect of these substances
is inhibited as can be done by what are known as flour improvers proteolysis during
fermentation is diminished and baking quality thereby improved.
Protease exists in malt extract and the softening action of malt extract on dough may be
partly caused by its presence. Malt extract is, therefore, sometimes useful in dealing with
a gluten-bound and over-strong flour.
Protease, if present in excessive quantities, can be detected by its action on a
cooled and solidified gelatin solution in which it causes liquefaction but the test is not
very satisfactory.
High proteolytic power is not necessarily associated with weakness and many
very weak flours, such as English, have feeble proteolytic activities. Also, it appears that
many flours that are poor gassers are also deficient in proteolytic activity. It is considered
that proteolytic enzymes are more sensitive to heat than are diastatic enzymes; hence, it
may be possible, by choosing the right temperature and other conditions, partially to
suppress proteolytic activity without interfering excessively with diastatic activity.
ENZYMES AND THEIR ROLE IN WHEAT TECHNOLOGY

The hydrolysis of lipids in bread and cereal products due to enzymic activity has been
reviewed by Hutchinson; it should be noted that lipase activity in oatmeal used to be a
matter of considerable concern for the oat-miller but today oatmeal, virtually devoid of
lipase activity, can be produced by prior steaming of the grain. An oatmeal dough that
shows no activity over 2 hours at 37°C. indicates that the meal will be satisfactory for

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storage and for biscuit manufacture.

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