Transcript Methods_of_Cooking

Methods of Cooking
The preparation of many foods involves the application of heat in
certain ways the choice of cooking method to be used will be
influenced by:
• Food to be cooked.
• Amount of preparation
• Facilities available ;fuel, storage, equipment etc
• Time available
• Needs of individual being catered for.
• Individual preference.
Methods of cooking are classified according to how heat is applied
Moist-heat applied through the medium of liquid
Dry – heat applied directly to food.
Frying – heat applied through the medium of fats or oils
Microwave – heat generated by electromagnetic waves.
Moist Methods
Relatively low temperatures are used which may prolong the cooking
time of some foods. The liquid medium may be water, steam, stock milk
,fruit juice wine or beer.
Moist methods Include:
• Boiling / Simmering
• Poaching
• Steaming
• Pressure cooker
• Slow Cookers
• Stewing
• Braising
Boiling
Food is cooked in boiling water to
tenderise them, the water reaches
100 degrees c which causes rapid
movement of the water molecules due to
heat transfer by convection currents.
It is best to boil vegetables in a small
amount of water for as little time as
possible to conserve their vitamins
Adv
• Water is readily available
•
Food is unlikely to burn though it
may disintegrate if overcooked.
Dis –
• Nutrients may be lost
• Some flavour is lost from meat
Suitable Foods
Muscular cuts of meat:
• Lamb- middle neck
• Beef –brisket, silverside
• Pork – Knuckle, ham
• Most Veg
• Eggs
• Pasta, Rice cereal
• Fish
Poaching / Simmering
Very gentle methods of cooking
Poached food is cooked in a
shallow pan of simmering liquid,
which can be flavoured. It is a
good way of cooking:
Suitable Foods :
•
Eggs
•
Fish
• Some fruits, such as pears and
peaches
Steaming
Steamed food is cooked over boiling
water, either on a hob or in an electric
steamer. A gentler method of cooking
The steam rises and cooks the food
without it being actually in the
water.(convection).
The food keeps more of its water soluble
vitamins. Steamers are economical with
fuel because several foods can be cooked
at once in layers
Pressure cooker
Adv –
• Economical on fuel
• Meals can be prepared quickly
• Nutrient loss is reduced though
heat destruction still occurs.
• Whole meals can be cooked in
one pan
• Tough cuts of meat can be
cooked quickly.
Dis –
Adv – Loss of nutrients is reduced as the • Careful timing is important to
food does not come in direct
prevent foods such as veg from
contact with the water.
being overcooked.
Makes the food easy to digest as it
has a lighter texture.
• Little attention is required while the
food is cooking except replenish the
water.
• Food is unlikely to be overcooked.
Dis –
• Food takes a long time to cook
Suitable Foods
• Potatoes & other Veg, Fish, pudding
•
Suitable foods
• Soups & stocks.
• Stews & casseroles
• Jam making & fruit boiling
• Vegetables
• Puddings
Slow Cookers :
Stewing
cooking can make cheap tough
Slow method of cooking on the hob
or in the oven for a period of
cuts of meat really tender. They
several hours. The heat is
can be plugged in and left all day.
transferred to the food through
Adva mixture of conduction and
• The pot can be left unattended
convention
little fuel is used
Adv
• Tough cuts of meat can be
• Tenderiser tough cuts of meat
tenderised
• Nutrients lost are kept to a
Dis –
minimum as the liquid is served
• Meat & poultry may have to be
with the meal
browned beforehand.
• Pulses & beans may not cook properly • Improves certain fruits as the
cellulose is softened eg rhubarb
Braising
• Large variety of stews &
Similar to stewing but uses less liquid,
casseroles can be prepared
cooked for several hours at a low
• A whole meal can be prepared in
temperature
one container.
Adv –
Dis –
• A whole meal cooked in one pot
• Long slow method of cooking
• Tough cuts of meat can be used
Dis – May need to be grilled at the end • Little variation in texture
to give colour
Suitable Foods
Suitable Foods
•
Beef, Lamb,Poultry
• Beef, Rabbit, lamb, Poultry, offal
•
Fruit
Dry Method
Higher temperatures are used in dry cooking
Roasting involves cooking foods in a hot
oven with a little fat turning occasionally
to give a crispy surface.
Heat is transferred by conduction which
causes the water to evaporate from the
food which concentrates the flavours in
the food
You can roast:
• meat and poultry
• potatoes and other root vegetables
Adv –
• Tenderises suitable joints
• Little attention is required except to
baste the joint
Dis
• A lot of moisture is lost by
evaporation
• Meat may shrink
• High temp may result in toughening of
protein
Baking
Baked foods are cooked in a hot oven
without adding any extra fat.
The heat causes the food to rise and
then set. It is important to ensure the
oven is hot , so that the process of
rising starts straight away.
It is important not to open the oven
door during baking as the cold, heavy
air that will get drawn in causes the
baked food item to sink.
In gas ovens the hottest part is the
top as the hot air rises to the top by
convection.
Many electric ovens are fan assisted
which means that a fan blows the hot
air around so that the temperature is
the same on all shelves, they also can
cook the food quicker so the cooking
time may have to be reduced
You can bake: Bread, pastry and cakes,
• Fish .potatoes.
Grilling
• Is the cooking of food by
Radiation. The surface of the
food is quickly sealed and the
flavour is well developed.
• The food must be moistened
with fat to prevent drying out
and turned frequently to ensure
even cooking.
• Food is placed on a very hot grill
until it browns, then the heat is
turned down until the food is
cooked through.
• The food should not be more
than 2.5- 3.5 cm thick to allow
heat penetration
• Grilled food can be cooked
indoors on a grill or outdoors on
a barbeque It is a good way of
cooking tender meat and
poultry, fish and vegetables
• Grilling is healthier than frying
as it uses less fat.
Barbecuing
Is a method of cooking where foods
are cooked on a metal grill over hot
, glowing charcoal, or on a modern
gas barbecue
The food is cooked by radiation,
from the hot coals and if charcoal
is used it gives the food a smoky
flavour.
The food needs to be turned
frequently to ensure even cooking.
The temperature of the coals must
be controlled so that the food
cooks right the way through and not
just on the outside.
If not cooked properly the food
may cause food poisoning.
Suitable foods are small meat and
poultry joints, sausages, burgers,
kebabs, fish . Sweet corn ,
mushrooms tomatoes & potatoes
Frying
• A Quick, convenient method of cooking which
involves high temperatures.
• The fat or oil used for deep fat frying must be
suitable for heating up to 200oC without burning.
• Reduced fat spreads have a high water content
and are not suitable for frying as the water
causes the fat to spit when heated and so is
dangerous.
There are four types of frying
• Deep
• Shallow
• Dry
• Stir
Deep frying
Involves the immersion of food in a pan
of hot fat. Deep fried foods are high in
Fat but
•
Do not allow oil to become too
Hot or it will smoke and rapidly
catch fire.
If it catches fire, turn off the
heat and cover with a lid or thick
damp cloth to exclude the oxygen
Oil should only be used a few times
because every time it is used the
oil molecules break up and start to
effect the flavour.
•
Less fat is absorbed if the oil is
very hot when the food is put into it.
•
•
Food that are deep fried ,should
be coated to prevent overcooking
and to prevent the food breaking
up and absorbing too much fat.
•
•
Suitable protective coatings
include, eaten egg, breadcrumbs,
oatmeal and egg, milk and flour
batter.
Shallow frying
•
When the food is placed in the hot
fat the egg in the coating coagulates
rapidly and thus forms a protective
layer around the food. The food
inside continues to cook by
conduction and retains its flavour
and texture.
Deep fat fryers are safer because
they control the oil temperature.
Food should be drained on kitchen
paper.
• Involves the cooking of food in a
layer of hot fat that comes half
way up the food.
• Heat is conducted from the base
of the pan to one surface of the
food at a time. This means the
food has to be turned at regular
intervals to ensure even cooking.
• Food that is shallow fried does not
necessarily have to be coated
beforehand as the frying can be
fairly gentle
Dry frying
Stir Frying
• Some foods e.g. bacon and • Originated in the Far East
sausages can be fried
and traditionally done in a
wok .
without the addition of fat
as
• All ingredients should be
finely chopped. into small
They contain sufficient fat
pieces so that it cooks
to
quickly.
prevent sticking to the pan.
• A teaspoon of oil is heated
in the wok and the food is
• Non stick pans are most
put in and stirred
suitable for this form of
continuously to ensure even
frying
cooking.
• Few nutrients are lost and
the food remains crisp and
well flavoured.
• It is a quick and healthy
method of cooking.
Microwaves
• Microwaves are radio waves.
they are absorbed by fat, sugar
and water but pass through
glass, ceramics and plastic
•
They move at the speed of light
and have a very high frequency,
i.e they vibrate millions of times
a second.
• If absorbed into an object the
vibrations of the microwave
agitate the molecules within the
object, causing friction, which
causes a rise in temperature as
the energy is converted into
heat energy so the food cooks
• Microwaves are reflected,
transmitted or absorbed by
different materials.
Reflection
• Microwaves are reflected
from metal which does not
heat up. Inside an oven,
microwaves bounce off the
metal walls, hit the food and
are absorbed by it.
Transmission
• Some materials e.g. paper,
china and some plastics allow
microwaves to pass through
them but do not heat up.
Absorption
• Some materials e.g. food
absorb the microwaves and
become hot.
As food cooks quickly there is
less chance of nutrients being
destroyed .
They can be used to defrost
food.