2. a.Improves the taste and food quality
b.Destruction of microorganisms -
Clostridium botulism and
salmonella. Moulds produce toxin
Aspergillus flavus - aflatoxin -
groundnuts, cereals and spices
OBJECTIVES
3. a. Improves digestibility - softens - connective
tissue – meat
• coarse fibres of cereals, pulses &
vegetables - digestive period - shortened &
GI tract - less subjected to irritation.
• Improves - texture - becomes more
chewable.
4. •Bursts - starch - digestion - more
easier, rapid & complete.
•Increases the access to enzymes
and improves digestibility.
d. Increases variety
e. Increase consumption of food
f. Increase availability of nutrients -
avidin
g. Concentration of food
5. Limitations of cooking
Thiamine - heat sensitive- lost -
cooking.
Water soluble vit. - leached into the
water during cooking.
Vit A & C - content - reduced -
oxidation & heat.
Quality - protein - reduced -
destruction of certain AA during
cooking.
9. 9
Boiling
• Immersing in water at 100C.
• Heat by conduction and convection food is cooked.
• Food brought to vigorous boiling.Temp cannot be
• Excessive evaporation of water and waste of fuel.
Food burnts – bottom
Dry crust – Top
Boiling – ex., Rice, eggs, dhals, potatoes, meat,
beetroot.
Excess water Sufficient water
Egg, potatoes dal, upma
10. 10
Advantages and Disadvantages
• Simple method
• No special skill &
equipment.
• Soluble starches
removed, rice grain
separated.
• Protein – denatured
• Starch - gelatinized
• Collagen – hydrolysed.
• Uniform cooking.
• Loss of nutrients – 30 – 70 % vit C.
• Loss of colour- Water soluble
pigments.
• Time consuming- Time and fuel
wasted.
• Loss of flavour and Texture. – No
taste, No flavour, over boiling – food
massy.
11. 11
Simmering
Foods cooked in a closed pan temp below
boiling point 82-99C of the liquid in which
they are immersed the process is known as
simmering.
Ex., cheaper cuts of meat, fish, cooking
custards,
kheer,vegetables and carrot halwa – soups.
12. 12
Advt :
Foods cooked thoroughly.
Scorching or) burning is prevented.
Losses due to leaching is minimum.
Disadvt:
Loss of heat sensitive nutrients.
More time and fuel is required.
13. 13
Poaching
• Minimum liquid temperature – 80-85C
Ex., eggs, fish and fruits.
Advt:
Very quick method.
Easily digestible – no fat is used.
Dis advt:
Bland taste.
Water soluble nutrients leached into water.
14. 14
Stewing
• Cooking in a pan with a tight fitting lid.
• Using small quantities of liquid to cover half the food.
• Liquid is brought to a boiling point, heat reduced to
maintain the cooking at simmering temp i.e., 98C.
• Stewing is a slow method of cooking – 2 to 4 hrs.
Advt:
Loss of nutrients by leaching does not take place.
Flavour is retained .
Dis advt:
Time consuming.
15. 15
Steaming
• Food cooked in steam.
• Steam generated by boiling water or liquid in a
pan so that the food is completely surrounded
by steam and not in contact with the water or
liquid.
• Food gets cooked at 100C.
• Steaming is generally done in special
equipment designated for the purpose.Ex., idli
cooker.
16. 16
Wet steaming
Double boiler is used for cooking the food.
Ex., Sauces, custards.
Water less cooking
In steaming, food is cooked by steam from added
water while in waterless cooking the steam originates
from the food itself.
Ex., Food wrapped in aluminium foil.
Dry steaming
Steam is in direct contact with the food
e.g. idli.
17. 17
Advantages and Disadvantages
• No attention
• Nutritive value maintained
no leaching and cooking
time is less.
• Easily digestible no fat is
added.
• Less chance of burning
and scorching.
• Texture becomes light
and fluffy.
• Steamed foods have good
flavour.
• Special equipment is
required.
• Many foods cannot be
prepared by this
method,e.g.rice.
18. 18
Pressure Cooking
• Small increase in temperature.
• Reduces cooking time.
• In pressure cooker, escaping steam is
trapped and kept under pressure so that
the temperature of the boiling water and
steam can be raised above 100C can
reduce cooking time.
19. 19
Heavy gauge aluminium
Pressure is regulated by weights placed upon
a release valve.
A safety valve is always fitted to prevent
pressure inadvertently building up beyond the
safe and specified level for the vessel
construction.
A common practice in the pressure cooking is
to allow a copious flow of steam from the
release valve before capping it with the
weights. All air is removed before the cooking
process starts.
20. 20
Advantages and Disadvantages
• Less time to cook
• Different items may be
cooked at the same time.
• Fuel is saved.
• Requires less attention.
• Nutrient or flavour loss
may be less.
• Food is cooked
thoroughly by this
method.
• There is an indication for
the completion of coking.
• There are less chances of
scorching or burning.
• Thorough knowledge of
using the equipment is
required. accidents can
happen.
• There may be mixing of
flavours.
• Food may be undesirably
soft.
21. 21
Dry heat methods
Medium of cooking – Air, Fat
Air - Grilling or broiling and baking.
Grilling – placing the food below or above or in
between a red hot surface.
Heat – radiation results in browning.
Heating most superficial, grilled foods are
reversed or rotated.
e.g., papad, brinjal, phulkas, sweet potatoes,
chicken.
22. 22
Advantages and Disadvantages
Quick method of cooking.
Less or no fat is required.
Flavour is improved.
Constant attention is
required to prevent
charring.
23. 23
Pan broiling or roasting
Advantages
• Improves the colour, flavour
and texture of the food.
• Reduces the moisture content
of the food and improves the
keeping quality,e.g.rava.
• It is easy to powder e.g. cumin
seeds and coriander seeds
after roasting.
• It is one of the quick methods
of cooking foods.
Disadvantages
Constant attention is
required.
Losses of nutrients like
amino acids occur when
the food becomes brown.
When food is cooked uncovered on heated
metal or a frying pan the method is known as
pan broiling.e.g. groundnuts and chapattis
24. 24
Baking
Advantages
Flavour and texture are
Improved.
Variety of dishes can be made.
Uniform and bulk cooking can
be achieved e.g. bun and
bread.
Disadvantages
Special equipment and
skill are required.
Cooking media hot air dry heat is combined with that of
steam. Foods baked are generally brown and crisp on
the top, soft and porous in the centre, e.g. cakes,
pudding and breads.
25. 25
Fat as medium of cooking
Saueting
Cooking in just enough of oil to cover the base of the
pan( greasing the pan) e.g.dosa.
Shallow fat frying
Larger amounts of fat used heat is transferred to the
food partially by conduction. E.g. paratha, chapati,
potatoes, fish, cutlets.
Deep fat frying
Food is totally immersed in hot oil and cooked by vigorous
convection currents and cooking is uniform on all sides of the
foods.temp – 180 – 220C.
26. 26
Advantages and Disadvantages
Taste is improved, along with the
texture.
Increases the calorific value.
Fastest method of cooking.
In shallow fat frying the amount
of oil consumption can be
controlled.
Sometime the food may
become oily or soggy with
too much absorption.
More attention is required
while cooking and care
should be taken to avoid
accidents.
The food becomes very
expensive.
Fried food takes long time to
digest.
Repeated use of heated oils
May produce harmful
substances and reduce the
smoking point.
27. 27
Combination of cooking methods
Braising
Combined method of roasting and stewing in a pan with
a tight fitting lid. The meat should be sealed by browning
on all sides and then placed on a lightly fried bed of root
vegetables. stock or gravy is added which should come
to 2/3 of the meat.Flavourings and seasoning are added
and allowed to cook gently.
28. 28
• Vermicelli payasam
• Vegetable curry
• Upma
• Meat cutlet
• Vegetable pulav
• Mutter paneer
Roasting and simmering
Saueting and simmering
Roasting and boiling
Boiling and deep frying
Frying and simmering
Frying and stewing
Combination methods
29. 29
Microwave Cooking
• Electro magnetic waves – magnetron
absorbed food and food becomes hot at
once.
• No medium of transfer of heat.
• Microwaves absorbed reflected by metals
and absorbed by foods.
30. 30
Energy of electromagnetic radiations excite
Water molecule. Positive charge
Negative charge
Electric field – microwave interacts – water dipole
Water molecules vibrate very rapidly in food 2,450
million times a second. Glass tray External
air vents
Control
panel
Door
Release
button
Identifica
tion plate
External
air vents
Door safety
lock system
Roller ring
Oven
window
31. 31
Advantages and Disadvantages
Microwave ovens cook
many foods in about 1/4th
of the time. No wastage of
energy.
Saves time in heating
Frozen foods. Thawing in
minutes or seconds. No change
- flavour,texture.
loss of nutrients minimized.
Washing easier, foods cooked
uniformly.
Preserves natural colour.
• Short period of cooking
food doesn't become
brown.
• Deep frying, shallow
frying, boiling not
possible.
• Careful operation.
• No blending of flavours.
