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Bakery
Ingredients
Wheat Flour, Water, Salt, Yeast,
Sugar, Shortenings, Milk, Chemical leavening agents, Spices, Flavorings, Fruits and
Nuts, Food Colours, Setting Material,
Cocoa & Chocolate
Bread Manufacturing
Straight Dough Process,
Sponge
Dough Process
Wheat is
classified according to
·
Hardness: 1. Hard wheat Þ a. Hard Spring b. Hard Winter c. Durum
2.Soft wheat
·
Colour of Kernel
Hard wheat:
Hard Spring and hard winter wheat: Desirable for Bread production. Flour of these type of wheat is
high in good quality protein from which strong, elastic dough can be made with proper
development. These doughs have good tolerance to bakeshop conditions w.r.t.
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. Hard wheat doughs have high water absorptive
capacities and generally have excellent dough handling properties when properly
matured.
Durum
wheat: Two varieties
1. Amber Durum –
Used for making alimentary pastes e.g. macaroni, sparghetti, noodles etc.
2. Red Durum -
Principally used as feed.
Soft wheat:
a. Soft Red
b. Soft white
SWs are used for
production of flour for cakes, pastries, cookies etc.
SWs are low in
protein, and they yield flours which have low absorption capacity and poor
tolerance to mixing and fermentation in bakeshop practice. They handle poorly
in bread baking equipment and are considered undesirable for commercial bread
production, but are highly desirable for the production of cakes, pastries and
cookies.
Composition of
wheat:
Bran 15%
Germ 2.5%
Endosperm 82.5%
Bran is high in nutritive value, but its
removal is necessary because sharp edges of bran tend to cut the cell structure
of loaf during proofing thereby affecting volume of bread.
Removal of bran is also necessary since
it is high in oil and thereby affects keeping quality of flour.
Average
composition of flour
Starch 70%
Moisture 14%
Protein 11.5%
Mineral (ash) 0.4%
Sugar 1%
Fat (liquid) 1%
Others 2.1%
FLOUR PRODUCTION
Wheat → Cleaning → Conditioning
↓
Breaking
↓
Reduction
↓
Bleaching
The manner in which particles of endosperm are separated is called ‘Separation’ whereas ‘Extraction’ refers to the percentage of flour, which has been extracted from wheat kernel.
TYPES OF FLOUR
Different types of flour are used for different types of end
product.
Characteristic of flours
are determined by percentage of separation obtained from 72% extraction.
First Patent 70%
separation from 70% extraction
‚ Short Patent 80%
separation from 70% extraction
ƒMedium Patent 90%
separation from 70% extraction
„Long Patent 95%
separation from 70% extraction
1. used as cake flour,
obtained from soft wheat
2. used for premium brands
of bread
3. used for featured brands
of breads
4. used for competitive
brands of breads
Hard wheat is used for production of yeast-leavened breads.
Soft wheat is used for production of chemically leavened products
such as cakes and pastries.
Amber Durum wheats are used for alimentary pastes in the production
of noodles, macaroni and similar products.
Generally Hard wheat is high in proteins, whereas Soft wheat is low
in proteins.
Bread flour should contain in excess of 10.5 % good quality protein
and not more than 0.4% ash.
Also, bread flour should have high absorption and good mixing
tolerance, which means prolonged mixing without breakdown of ‘gluten.’
Cake flour should have less than 10% protein and 0.4% ash, and
should have low water absorption.
FLOUR ENZYMES
2 enzymes essential for bread production
β- amylase – susceptible to heat
‚ α- amylase
These enzymes are synthesized
or activated at the time of sprouting
Dextrin and a portion of soluble starch --- β-amylase -----® maltose (essential for active yeast
fermentation)
Soluble starch-------α- amylase ------® dextrins
α- amylase is more heat stable than β- amylase and can survive at 75 - 80˚C.
MALT FLOUR
Prepared from barley or wheat, which have been sprouted, dried and then ground into flour. Malt supplements are added to flours in order to increase gas production by providing fermentable sugars for yeast.
BLEACHING
Employed to destroy the natural yellow or creamy colour of flour
that is due to presence of plant pigments e.g. carotenoids. Bleaching could be
chemical or enzymic.
Maturing of flour gives more machinable and better baking dough.
CHARACTERISTICS OF FLOUR – required for the production of quality bread
1. Colour : trace of creamish
colour is desirable
2. Strength : strong or weak
flour , have capability of producing a bold, large volumed, well risen loaf
3. Tolerance : ability of flour
to withstand the fermentation process and to produce satisfactory loaf over a
period of time.
4. High absorption : ability to hold
water without additional mixing for full development of dough.
5. Uniformity : also imp.
PH-Value
Satisfactory range is usually between pH 5.5 & 6.5.
Acidity plays a part in maturing gluten during fermentation and
increase gas production by increasing enzyme activity. The acidity produced in
fermentation improves flavour and palatability, flour acidity can be increased,
if desired by controlled chemical treatment.
If pH is < 6.1-6.2, taken as indication of chlorine treatment in
bleaching process. This treatment is of extreme importance in the control of
quality in high ratio cakes where pH value would be expected to fall in the
range of 4.6 to 5.0 depending on the characteristics of the wheat being milled.
STARCH
Starch granules are very resistant to mechanical alterations and
also resist chemical changes.
A raw starch granule will only absorb water to about one-third of
its weight but when cooked absorbs several times of its weight of water and
also increases to several times of its original size.
When starch is cooked in water the small granules do not change
until a temp. of about 57° to 70°C is reached. Process is known as gelatinization. Complete
gelatinization takes place at 88°C. i.e. when starch is heated in water to a sufficiently high
temperature the granule absorbs water and swell to a larger size.
In dough fermentation, starch must be changed to sugar for proper
yeast activities, which results in gas production (leavening). Enzymes present
in flour change starch to sugar. Amylase act on damaged or broken starch
granules which result during milling process (amount of damaged starch is
usually 5-7%).
Diastatic malt: if percentage of a-amylase is less in flour. DM is used for additional
enzymatic activities.
FLOUR TESTING
Methods are grouped into four categories,
1. Chemical analysis
2. Physical methods
3. Physical examination
4.
Baking test
Chemical
analysis: include
a) MOISTURE- Flour should have 14%
moisture. Excessive moisture adversely affects KQ and is undesirable from
economic stand point also.
b) ASH- determines mineral matter in flour.
Considered as a measure of the degree of separation of flour from a particular
wheat blend.
c) PROTEINS- quantity estimation but from
baking point of view, both quality and quantity are important.
d) MALTOSE- indicates activity of b & a amylases.
Physical
methods: include methods, where equipment is used for
determining flour quality
a) amylograph ® amylase activity
b) Farinograph ® strength of flour
c) Extensograph ® loaf volume potentialities
d) Mac Micheal Viscometer ® amount of bleaching that flour has
undergone (Bleaching incidentally weakens proteins)
e) PH Value ® acidity or alkanity
Physical
examination: include
testing for colour, by Pekar colour test, which indicates the degree of
separation
Baking
test: include a standard lab – scale baking test for
evaluation of flour quality.
STORAGE OF FLOUR
reasons for storage
1. economies to tide over periods of
difficulties.
2. colour improvement
3. maturing
Unbleached flour can be stored for a longer period than the
bleached flour.
Uniformity of water quality is required in order to
obtain uniform results in the product. Hardness and pH are the major variable
parameters, which determine water quality.
1) Sea water
2) Deep earth water
3) Natural water
Water can contain minerals, can easily get contaminated, and can
pick up natural impurities.
1) Soft water – low content of dissolved
minerals.
2) Hard water – contains dissolved
minerals. Can either be of temporary or permanent hardness.
3) Alkali water – when alkali is present in
soil
4) Acid water – due to mines, wastes etc.
5) Saline water – contains traces of common
salt, thereby making it sensitive to taste.
Any of the above type may be turbid due to presence of suspended
matter such as clay, silt, fine sand or like material.
Any water which is fit to drink may be used in the making of bread.
Water of zero hardness is often employed in the production of biscuits and
cakes because it is considered to yield better and more uniform product.
Medium hard water yields excellent result in the production of
bread.
Several functions
v
It makes
possible the formation of gluten. Gluten as such does not exist in flour, only
when flower proteins are hydrated; gluten is formed.
v
It control
the consistency of dough.
v
It assists in
the control of dough temperature.
v
It dissolves
salts; suspends and distributes non flour ingredients uniformly.
v
It wets and
swells starch and renders it digestible.
v
It also makes
possible enzyme activity.
v
Water keeps
bread palatable longer if sufficient water is allowed to remain in the finished
loaf.
Medium hard water does not affect yeast
activity and the gas retention is also good. This water is best suited for the
bread production.
Soft water ; very hard water ; presence
of Nacl, Iron, more than normal acids ; and alkaline water affect yeast
activity and proper gluten development (thereby poor gas retention), therefore
are not suitable.
SALT
·
Common salt
or table salt is used for bringing out the flavour of other ingredients, used
in cakes and other products.
·
Salts is also
used as an adjustment of sweetness, if product is too sweet. Sugar retains
moisture in cake, therefore, excessive sweetness is toned down by increased
amount of salt.
·
Salt lowers
caramelization temperature and aids in obtaining crust colour.
·
In bread
production salt is mainly added for taste, also improves flavour.
·
Salt act
toughner, without salt dough remain wetty, therefore improves grain and texture
of loaf by strengthening the dough, thus indirectly helping colour, grain and
texture.
Amount of salt to be used depends on
several factors, mainly upon
Type of flour: Weak flour takes more
salt, because salt gives strengthening effect to proteins.
Formula used : Richer formula takes
higher percentage of salt, as compared with a leaner formula.
Mineral content of water : Hard Water
needs reduced amount.
Under normal
conditions amount of salt ranges in between 2 to 2 ¼ %
Characteristics of table salt required
for use in bakery.
v
Complete
solubility in water
v
Should give a
clear solution
v
Free from
lumps
v
Pure as much
as possible
v Free from a bitter or biting taste
v
In bread
making, yeast lighter the dough and impart a characteristic aroma and flavour
during the process of fermentation, which is a general term, covers aerobic and
an aerobic changes brought about by microorganisms and includes production of
CO2 , alcohols, acids and
some other by products.
v
There are about 3,300 known species of yeast.
Only a few of them are used for baking trade.
v
Yeasts have
seen found in nature wherever there is sugar. The surface of rip fruits
especially grapes and apples. The sap that has oozed from trees and the nectar
of flowers also furnish food material for yeast in nature. Yeasts are present
in soil, especially in vine yards and orchards and on plants. They pass the
winter in a dormant form in the soil and are carried about by insects and wind.
Size
and shape:
Variable, depending on species and age.
Round or plump ovals.
diamater 1/2500 to 1/4000 inch
Single cell composed of cell wall, cell
membrane, nucleus, protoplasm, vacuoles and various granules.
Methods
of Multiplication:
Budding,
Sporulation or starvation, sexual.
Production
of Yeast :
A Pure strain of Saccharomyces
cerevisiae, suited to Indian Climate is selected. After successive pure
culture stages, it is added to the clarified and diluted cane molasses in
fermenter at temp 300C or 860F. Temp, pH, mineral
addition, aeration rates and incremental feeding of sterilized molasses are
maintained. Obtained cell mass is washed to make it free from impurities and
concentrated to about 30% dry matter, which is then processed either for
compressed or active dried yeast.
Enzymes: small amount of
several enzymes are synthesized by yeast, including protease, lipase,
invertase*, maltase* & zymase* (* imp. only)
Protease- can soften flour proteins,
therefore can cause great changes in properties of dough, but, in normal
baker’s yeast protease are intracellular and are not able to pass through cell
membrane.
Lipase- also intracellular. Acts on fat
encountered within cell, especially during sporulation.
Invertase- also intracellular.
Sucrose(cane sugar) enters the cell
wall, is changed to glucose and fructose.
These sugars then diffuse through membrane.
Maltase – maltose to 2 units of glucose
(or dextrose)
Zymase- group of enzymes. Finally turns the trick in dough
fermentation of sugars by yeast.
Fermentation –produced CO2 raise
the dough.
v Balanced nutritional diet of sugar
v Nitrogen
v Minerals
v Vitamins
v Water, air ,opt
temp., enzymes, O2 , optimum pH, nutrient concentration & time.
Simultaneously
produced alcohol contributes to bread aroma & flavour.
Yeast prefer acidic environment, can tolerate pH as low as
pH 2. Optimum pH is near 4.5.
Two forms of Yeasts are commercially
available
1. Compressed baker’s yeast
30% solids
& 70% moisture
Storage life
at refrigeration (20C)- 4 to
5 weeks after that loses in fermenting
power .
Temp. below –30C
destroys life of yeast .
2. Active dried yeast –small dried pellets.
Packed in N2
filled tin plate containers.
92% solids
& 8% moisture
for storage
refrigeration is not required. 450F or 70C is optimum
storage temp.
Two types,
commercially
1. simple sugars – glucose or dextrose, fructose & galactose
2. compound sugar – sucrose ,maltose ,lactose etc.
SUGAR
properties
1. Hydrolysis
Compound sugars --- enzyme/acids -- ® simple sugars
Maltose------maltase*------
® glucose
Sucrose------ invertase*----® fructose +dextrose (rapid)
(*enzymes present in Baker’s Yeast)
lactose
-----galactosidase*-----®glucose + galactose (*enzymes absent in Baker’s Yeast)
2.
Yeast fermentation
Simple sugasr
-----------------® C02 + alcohol
3.
Rate of fermentation
Additional
amount of sugar speeds up fermentation within a limits.
4. Residual sugars
2% of added sugar is
utilized in fermentation process, rest is called residual sugars.
5.
Sweetness and Flavour
In studies of comparative sweetness, sucrose is used as standard.
Order of sweetness
Fructose> Invert sugar> Sucrose> Dextrose> Maltose> Galactose> Lactose
6.
Hygrsocopicity and Hydration
Ability of a substance to absorb moisture and retain it.
7.
Heat susceptibility
On Heating, molecules combine to form coloured substance called
‘caramel’. Sugars vary in their heat sensivity i.e.the temperature at which
they begin to caramelize.
Fructose, Maltose, Dextrose are more sensitive.
Lactose and Sucrose are less heat sensitivity.
By lowering the pH of the sugar solution, fructose and dextrose
become less sensitive.
8.
Browning reaction
Reducing sugars, when heated with proteins, react to form dark
compounds called melanoidins. In early stages, melanoidins resemble caramels in
colour, odour and flavour. Further reactions causes them to become black and
insoluble.
Sucrose alone of the sugars discussed will not react with proteins.
Fructose and dextrose in general, are most active in browning reaction. With
all sugars, except sucrose, the browning reaction is accelerated by raising the
temperature and pH. Both caramelization and browning are important in
determining colour of baked products.
9.
Solubility and crystallization
Difference in
solubility of the sugars can be used to control crystallization in products
that require higher amounts of sugar.
10. Softening
Ability of sugar to hold water to tenderize baked products
and thereby improves texture, volume and symmetry
Functions of
sugar in bread :
1. Source of energy for yeast activity
2. Flavour is improved and crust colour is darkened by addition of
sugar.
3. Texture of grain become smoother and finer with added sugar. The
basis of this is not well understood, but may be related to the action of
sugars on delaying the gelatinization of starch and the denaturation of
protein.
means fat or
oil used to tenderize baked products or fry products .
Composition
Glycerol + Fatty acids --------® Triglycerides
(one molecule) (3 FA)
FATS: mixture of triglycerides solid
at RT
OILS : liquid at RT
SPECIFIC GRAVITY ratio of the
weight of any given substance to the weight of equal volume of water.
water> fats or oils
SOLUBILITY IN WATER: nil, form
emulsion
Soluble in
organic solvents like ether, benzine and CCl3
FUNCTIONS
In bakery
foods, fats provide nutrition, flavour and act as tenderizers; and aid in the
development of the physical structure of baked foods.
In bread
production fats impart tenderness making it more palatable, assist in gas
retention by making gluten more airtight and render better volume. Formed dough
has greater extensibility and bread has improved crumb, fine texture and crust
of loaf.
In production
of cakes, creaming value of shortening is important for the so-called ‘sugar
batter’ method of mixing. Sugar-batter method means that fat and sugar are
creamed first. Hydrogenated fat cream well.
Butter is used
for flavour but has inferior shortenilng value. Butter does not cream too well
and lacks uniformity.
Creaming power
is the ability of a shorting to entrap and to retain air cells when the
shortening is vigorously agitated, especially when it is in contact with the
other ingredients of a cake batter such as sugar and flour.
VEGETABLE OIL PROCESSING: Several stages
1.Purification
2.Bleaching
3.Hydrogenation
4.Deodourization
5.Chilling
6.Tempering
MARGARINE:
Basically, it
is intended as substitute for butter. Both are almost identical in composition.
The major raw material used is hydrogenated oil for margarine manufacture.
There include cotton seed oil, corn oil, soy bean oil, peanut oil. Margarine
manufacture consists of mixing of fat with other water soluble additives
including skim milk .The mixture is then strongly agitated to form an emulsion.
The emulsion is then passed through the coolers and the crystallizing unit,
then wrapped and packaged.
Baker’s
margarine is different from table grade margarine, they do not have resistance
of melting point and consistency.
BUTTER:
:80 – 81% milk
fat, 14% water, salted butter contains 1 – 3% salt
Butter is
considered to be the best of all baking shorteing from a flavour stand point.
Creaming quality of butter is poor.
Creaming
quality is controlled by:
a) Chemical composition
b) Crystal
structure of shortening
c) Temperature
at which shortening is used
d) Granulation
of sugar used.
CHEMICAL REACTIONS OF FATS:
The quality of
fats is affected due to certain chemical reactions. Some of these are:
HYDROLYSIS: in presence of water
Triglycerides----------® free FAs + glycerine
Excessive free
FAs cause foaming, reduce the smoke point and render the fat unsuitable for
deep fat frying.
OXIDATION: in presence of air and water in fat. little important in baking.
SMOKE
POINT: depends on presence of fatty acids.
Greater the % of free FAs, lower the SP.
STORAGE OF SHORTENING: 70 to 80º F or 21 to 26.6º C
·
Not to be stored near odourous
materials, since it can absorbs odour.
·
Avoid exposure of light, O2, heat or
high temp.
Emulsion of
fat in a water solution of protein, sugar and minerals.
WATER 87.75%
TS 12.25%
Fat 3.50%
Proteins 3.25%
- (80% casein, 20% albumin)
Minerals 0.75%
Lactose 4.75%
Specific
gravity 1.025 -1.035
TYPES OF MILK:
1) Fresh
products- Liquid whole milk, skim milk, butter milk etc.
2)
Concentrated products – Condensed whole milk, CSM, Butter sweetened condensed
whole etc.
3) Dry
products – Dry whole milk (WMP), SMP, Whey powder etc.
ADVANTAGES /FUNCTIONS:
·
Increased absorption and Dough
strengthening
·
Increased mixing tolerance
·
Longer fermentation
·
Better crust colour
·
Better grain and texture
·
Increased loaf volume
·
Better keeping quality
·
Better nutrition.
Advs of Leavening:
·
Products are light, therefore easily
chewed.
·
Porous structure of products facilitates
digestion by increasing contact area for the activities of digestive juices.
·
Products are more palatable and
appetizing.
METHODS OF LEAVENING
1. By means of
air (mechanical)
·
By creaming action
Air is whipped
into the shortening and sugar during creaming and expands when heated in the
oven to cause the products to rise. e.g. Old fashioned pound cake.
·
By beaten eggs
Beaten egg
become fluffy and foamy because of whipped air.
2. Liberating carbon dioxide gas in the dough by means of yeast
action e.g. Bread.
3. Producing leavening action by use of chemicals.
e.g.
i.
Baking soda
ii.
Baking powder
iii.
Baking cream
iv.
Ammonium carbonate
4. Water Vapour- In oven produced water vapour act similarly like
CO2 produced by yeast.
BAKING SODA AS A LEAVING AGENT
Sodium
bicarbonate NaHCO3
2NaHCO3-------heat----à CO2 + H2O + Na2CO3 (washing
soda)
CO2
is also liberated when baking soda is mixed with an acid, either hot or cold
If soda is
used alone, residual washing soda react with shortening and form soap to give
unpleasant taste and brown colour to the products.
BAKING SODA + AN EDIBLE ACID INGREDIENT
To avoid
undesirable results obtained when soda is used alone, some acid ingredients are
used with BS.
Reaction of
them with soda also gives CO2 for leaving.
Some acid
ingredients:
·
Sour Milk
·
Honey
·
Molasses
·
Invert sugar
·
Lemon juice
·
Butter milk
Commercially
it is not practiced, because it is extremely difficult to achieve uniform
results by using above ingredients.
with BS.
The result of
this search was the mixture commonly known as baking powder.
BAKING POWDER
Produced by
mixing an acid reacting material and sodium bicarbonate with or without starch
or flour as a filler. Generally Tartarate, Phosphate and Sulphate powders are
used as acid ingredients.
AMMONIUM CARBONATE AND AMMONIUM
BICARBONATE
Used to
a small extent. Use is limited to certain types of cookies. Adv of there
leavening agents is that they decompose into two gasses and does not leave a
solid residue.
Disadvantage,
is that ammonia gas solublize in water therefore products with high moisture
content give a disagreeable taste and odour. Therefore use is limited to those
products which are small so that ammonia fumes can bake out.
Used
comparatively in small quantities in baked product. There presence improves
eating qualities and physical characteristics.
·
Cinnamon
·
Cardamom seed
·
Ginger
·
Cloves
·
Nutmeg
·
Mace
·
Poppy seeds
·
Caraway seeds
·
Seasame seeds
·
Allspice
STORAGE OF SPICES
Volatile oils
in spices are responsible for aroma and flavour. Therefore storage of spices
require airtight container in dry, cool and airy place.
Flavor may be
defined as the sensation of smell and taste mingled. Flavour gives uniqueness
to the product.
General
components of taste are: Sweetness, sourness, saltiness and bitterness.
There are
various sources through which the baked product can acquire its unique bakery
flavour.
1. During the processing of the product.
i.e. during
baking, fermentation etc.
2. Flavour of the blend of the various basic ingredients.
3. Flavour Additives: can be divided into 3 groups.
a. Natural
·
Basic ingredients
e.g. forms of
sugar and syrups i.e. honey, molasses, malt syrups, ground fresh fruit, cocoa,
chocolate etc.
·
Essential oils of citrus fruits
b. Synthetic
c. Imitation- never used alone, used with natural flavour.
CLASSIFICATION OF FLAVOURS
1. Non-alcoholic flavour-prepared by dissolving ingredients in
glycerin, propylene, glycol or vegetable oil. Flavour is retained during by
reduced vaporization.
2. Alcoholic entract –flavours are dissolved in ethyl alcohol.
Suitable for icing and fillings.
3. Emulsifies –flavours are dispersed in gum solution.
4. Powdered foavourings –prepared by emulsifying components in heavy
gun / water solution, then spray dried to form powders.
CAUSES OF OFF FLAVOURS IN BAKED PRODUCTS
1. Inferior ingredients
2. Unbalanced formula
3. Inferior flavorings
4. Wrong pH
5. Excessive soda
6. Faulty baking and processing
7. Unclean pans
8. Cheap and wrong type of packaging and wrapping materials
9. Improper storage of finished products
10.
Dirty and defective transportation
A variety of
dried and processed fruits and nuts can be used in baked products to produce
different types of flavours and finishes.
DRIED FRUITS:
·
Currants
·
Sultanas
·
Raisins
·
Dates
·
Sugar preserved fruits and peels
·
Glace cherries
·
Crystallized cherries
·
Crystallized fruits
·
Angelica
·
Ginger root
· Crystallized flowers
NUTS:
·
Almonds
·
Walnuts
·
Pistachio nuts
·
Cashew nuts
·
Ground nuts
· Coca nuts
Eyes appeal of
the product is enhanced by the use of colour.
Guidelines for
the use of colouring materials
a. To supplement deficiencies in colour e.g. yellow colour is used to
conceal the lack of butter and eggs in dough.
b. To increase the eye appeal and to complement a definite flavour.
c. To introduce varieties and interest to decorate products.
REQUIRED CHARACTERISTICS OF COLOUR IN
MATERIALS
1.Harmless
2.Stable
against the action of acids, alkalis, SO2, high temp, day light and
long storage
PRIMARY COLOURS
Red, yellow
and blue, they produce secondary colours when mixed.
Yellow +
blue----------à green
Yellow + red
--------- àorange
Red + blue
------à violet
Natural
colours ---à obtained from animals or plant sources.
e.g.
Cochineal or
carmine
Saffron
Turmeric
Annatto
Chlorophyll
Caramel
Artifical colours----à prepared from coaltar. They are anilive dyes.
Required for
the products like Jams, Jellies, Icing, Yoghurt etc.
They cause
thickening of fruits syrup (Jam, Jelly) or other raw material to form a gel or in preventing stickness of icings.
Ingredients are known as gums. Most of these are carbohydrates in nature and
are obtained from plants (except gelatin) or sea weeds.
GELATIN
·
Derived from cartilage or bone of the
animals.
·
Pure gelatin is transparent brittle
substance without colour, smell or taste.
·
Available in sheet form or as
crystalline powder.
·
Dissolves only in boiling water. In hot
water it swells and absorbs about 10 times water. Prolonged boiling destroys
qelling properties.
·
Excessive amounts make products tough
and rubbery.
·
1% concentration set on cooling.
·
Derived from seaweed.
·
Available in powdered or fibrous
form.
·
Also called vegetarian Gelatin.
·
Insoluble in cold water.
·
Dissolved in boiling water, produces
slightly cloudy gel, slightly less tough than that one formed from
gelatin.
·
10% concentration set on cooling.
·
Boiling does not destroy setting
properties.
Used in jam production.
·
Naturally present in most of the fruits
but amount is variable.
·
Water-soluble and in presence of sugar
and acid form gel.
·
Commercially prepared from citrus fruit
pulp or papaya, guava etc.
Extremely pure form of gelatin obtained from swimming bladder of
various fish. Due to high price, not used widely.
Derived from seaweed.
Used as
stabilizer in emulsions, generally in milk, since it reacts with casein to form
excellent firm but tender gel.
·
Widely used in the production of various
bakery and dried milk products. e.g. cakes, pastries, pies, cookies etc.
·
Provide bulk to the mix and a
characteristic colour and flavour to the product.
Chocolate and
cocoa are produced from cocoa beans (fruit or seed) of cocoa tree.
Manufacturing of cocoa (click here)
1. Dutch-process cocoa
2. Natural cocoa
Straight
Dough Process: Short time formula is selected
Sponge Dough Process:
Longer time is required.
Combining
ingredients
1. Yeast + water + sugar at 110ºF
2. Shortening should be added after proper wetting of flour.
Essential factors for making good yeast leavened products:
·
Mixing of dough
·
Time
·
Fermentation
Fermentation period (straight dough process)
Temp.
80º F
RH 78 %
Over fermentation may result in
·
Pale crust colour
·
Sticky dough
·
Poor symmetry
·
Poor flavour
Lack of fermentation has opposite results.
METHODS OF BREAD
MAKING
1 STRAIGHT
DOUGH PROCESS (click here)
2. SPONGE DOUGH PROCESS (click here)
OILSEEDS AND NUTS
Used mainly as a source of oil but they are also rich in protein
therefore also used as protein supplements in human diet.
Groundnut
Uses :
·
As oil source
·
Manufacture of confectionary
In
Consumption of
oil from fungal infected nuts is a health hazard. When MC is > 8%, probability of fungal infection. GN should
be dried to safe level soon after harvesting and stored at RH < 70%.
·
It is one of the most important fats
used for making margarine.
·
Large quantity of GN is used to
manufacture vanaspati.
·
Also used in preserving fish.
·
De-oiled cake is used as cattle feed.
Rapeseed- Mustard
Three species
·
Brassica compestris
·
Brassica juncea
·
Brassica nigra
1. oil is used for edible purpose .
2. de-oiled cake for cattle.
Sesame
·
Important oil of domestic consumption in
·
Seeds are edible as such or fried
·
Decorticated seeds contain 25% oil
Cotton seed
Cottonseed oil is a by-product of ginning cotton.
Proportion of cotton to cotton seed is 3:1
Seeds
are of two types –
·
fuzzy- i.e. consisting of outer fluff or
fuzz
·
Non- Fuzzy
Fuzzy seeds
possess better properties for processing into edible oil.
Two methods of
oil extraction
·
Decortificated method- gives high-grade
oil.
·
Under decortificated method – oil with
poor acceptability and loss of oil.
Deoiled meal
is used as cattle feed
Coconut
Two purposes –
1. Used in edible product preparation
2. Oil extraction
Oil is extracted from dried coconut meal or copra.
Yield varies from 57-75%
§
Poor in unsaturated FAs
Oleic and
linoleic acids ® 9%
91% ® saturated FAs, higher %age of lauric and myristic FAs
§
Absorbed easily® extensively used for edible purpose.
§
Industrial applications
Manufacture of soap,
vanaspati, margarine, and pharmaceutical preparations.
Nuts or seeds or fruits consist of an edible, usually fat
containing kernel surrounded by hard or brittle shells. In addition to superior
quality protein and high oil content, they are also good sources of minerals.
Kernel ----- 2% minerals with
K & P
Shell ------- Ca, Na, Mg,
& Fe
Ways in which Nuts are used:
Roasted, Salted, Cooked or some processed foods prepared from protein rich nut flour and used as weaning food for children. Also used in ice cream, cake or Biscuit making.
PROCESSING OF
NUTS
Almost all the nuts require dehusking before further processing. It
can be manually or mechanically.
Dirty nuts are washed and then dried.
Some nuts marketed in the shell are bleached to remove all the
stains including those due to sunscroch and disease to give a uniform colour
throughout. Bleaching is done by sulphur-di-oxide or by dipping the nuts in
suitable bleaching.
Nuts in the
shell keep well for long period, specially when cold stored. But, the kernels
undergo rapid deterioration and may become mouldy or rancid. Therefore they are
dried and packed in moisture proof containers.
PROCESSING OF OILSEEDS & NUTS
Oils
and fats do not occur free in nature. They occur in animals or plant tissues
from where they are isolated, refined and processed for specific use.
PRESSING
About 20% of total edible oil production in country is by ghani
sector and it is of the consumer’s preferences due to its natural flavour and
taste.
Modern method
of oil extraction includes the use of high-pressure expellers. In this process,
material is cleaned, tempered and dehulled, crushed or flaked and then passed
through the expeller to extract oil. Deoiled cake is good cattle feed. About
50% of the produced oil is obtained by this method.
SOLVENT EXTRACTION
Pressed cakes obtained from expellers contain appreciable quantity
of oil. Therefore method is not efficient. Therefore SE alone or in combination
with above method is used. If oil content in material is very low then this
method is the only practical way to remove oil efficiently. Various solvents
are used but hexane is most common. After extraction solvent is removed from
oil. Residue(deoiled meal ) can be processed as edible flour. SE in our country
produces one-tenth of the oil.
REFINING
Oil extracted by the above methods is crude and contain many other
constituents like FA’s, unsaponifiable matter, gums, waxes, mucilaginous
matter, variety of colouring matter, metallic contaminants, undesirable
odoriferous constituents etc.
In refining
suspended particles are removed by filtration or centrifugation.
FAs are
removed by alkali treatment.
Pigments are
removed by bleaching using adsorbents like activated earth, carbon or in
special cases chemical bleaching agents.
Finally, oil
is deodorized by injecting steam through the heated fat kept under reduced
pressure.
HYDROGENATION