Yazar admin on Şub 22nd, 2009

Why Do We Cook Food?

Many foods can be eaten raw but our diet would be different if we didn’t cook at all.

The cooking process

Ø adds variety

Ø makes some foods more digestible

Ø makes some foods more appetising

Ø makes some foods easier to eat (e.g. meat)

Ø destroys any bacteria that may be present

Ø destroys naturel toxins (e.g. in kidney beans)

Ø reduces bulk (e.g. spinach)

Ø thickens and sets (e.g. egg dishes)

1.2. The Effects Of Heat Upon Foods

Secondly, we must look at the effects of heat upon foods to appreciate the different process involved and how it affects the food we eat.

Ø PROTEIN : Coagulates and gradually changes to become firmer and more easily digested, although over-cooking toughens it.

Ø FATS : Melt, which can be useful in cooking process. Too much fat in the diet causes obesity and difficulty with digestion.

Ø CARBONHYDRATES : Generally we can look at the carbonhydrates under two headings:

a) in dry heat the sugars and starches change colour from white to golden brown, then (with prolonged heat) to dark Brown(caramelize), after which they burn.

b) in moist heat starchess will gelatinize as the granules swell and burst, so creating a thickening agent; sugar will dissolve, become syrupy as further heat is applied and will eventually caramelize.

Ø VITAMINS : Fat-soluble A and D are lost in moist methods of cookery, nor are they destroyed by heat. Vitamins B and C are water-soluble and so can be lost in moist cookery unless the liquors are utilized for sauces. Both of these vitamins are also destroyed by high temperatures, as in pressure cooking.

Ø MINERALS : The breaking down of food in cooking makes it more easily digested;

any minerals thus become more available to us.

Generally we can look at the methods of cookery under two headings:

Dry : grill, shallow fry, deep fry, bake, roast

Wet : boil, braise, steam, poach

1.3. Dry Cookery Process

1.3.1. Grıllıng

This is a fast method of cooking and so tender foods may be cooked in this way.Grilling is by radiating heat under or over a gas flame are electric grill. The food needs to be moistened with fat or oil to prevent it becoming dry whilst cooking. Pieces must also be cut evenly and turned often during grilling to ensure even heat distribution. The heat affects the surface of the food quickly so sealing in the juices, but it is very easy to overcook and dry or burn the food. Because of the radiated heat, it is possible to simply Brown foods under the grill (called gratination) to assist in good presentation. For example, Cod moray is sprinkled with grated cheese and breadcrumbs and grilled to give it that browned effect, which is pleasing to the eye and gives the surface a crunchy texture.Grilling is suitable for snack meals, à la carte service and for cooking foods for those on fat reduced diets.


Suitable foods for grilling

Ø chops and cutlets

Ø sausages and burgers

Ø young, whole chickens and chicken breast

Ø liver and kidney

Ø fish fillets and small whole fish

Ø tomatoes and mushrooms

Ø steaks (rump, sirloin, filet)

1.3.2. Shallow Fryıng

There is the method of shallow frying, using a frying pan, which is perhaps what comes to mind when the term is used. There are also variants on this, using a work or a sauté pan.

a) Cooking in the frying pan:

This is a fast method of cookery, again suitable for tender foods. A thin layer of fat or oil is put into a shallow frying pan and food is placed in the pre-heated pan, presentation side first. Conducted heat from the base of the pan cooks the food that is in contact with it.It is advisable to turn food over once only as it may be damaged by

frequent turning. This style of frying can be slow if required, in which case foods need not be coated first (e.g.onions). However, as with deep frying, fast cooking requires a coating (as for example, with fish cakes). For those on a fat reduced diet it is possible to cook in a non-stick pan without fat, or use a very light layer

of oil, applied by oil spray.

Suitable foods for shallow frying

Ø fish fillets or whole, small fish

Ø tender cuts of maet, chops and cutlet

Ø liver and fidney

Ø fish cakes and meat rissoles

Ø beefburgers and sausages

Ø onions

Ø shredded vegetables

Ø eggs

b) Cooking in a wok

The wok is a frying pan made from very thin metal in a hemispherical shape, which allows oils to run back to the bottom. The work provides a very fast method of cookery, typical of the east. Foods are cut up into shreds or strips and tossed over a high flame until lightly cooked and still slightly crunchy. Foods tend to keep thier colour

well, their flavors are enhanced and low-fat cookery can be achieved.

c) Cooking in a sauté pan

Sauté is a term often used as an alternative to shallow fry. A sauté pan is heavierbottomed than a frying pan and allows slower cooking. Meat and poultry cuts are usually sautéed, which can also involve being tossed in the pan or turned over frequently, a method which is unsuitable for delicate flesh, such as fish. Sauces can be made around the food in the sauté pan to capture the nutrients and flavors that may otherwise be lost.

d) Deep frying

This is a fast method of cookery, and so suitable for tender foods. It requires the total immersion of the foods into

hot fat or oil. The heat from the oil penetrates the food and so cooks it. It is important to remember that raw foods such as sliced potatoes must be very well dried first or the moisture on them will cause the hot fat to ‘spit’.

Suitable foods for deep frying

Pieces of fish

Pieces of meat and poultry



Other vegetables


Made-up foods

Except for dough and potatoes, these foods would be spoilt during frying by the oil

being absorbed into the food and by loss of nutrients, unless they are sealed by coating them

with milk/egg and flour, or flour and batter, or flour, egg and breadcrumbs. The reason we

use protein foods, such as milk yolk egg is that protein coagulates as soon as it is immersed

in the hot oil, forming a very effective protective coating.


leave a deep fryer unattended heat the fat higher than recommended move a friture while it is hot

allow fat to smoke-this means it is near ‘flashpoint’.


Temperatures for deep frying

Temperature                                                (C) Foods                                             Timeº

165-170° C                potatoe chips(blanching) white meats choux paste                  5 minutes

175-180 °C                whole fish                                                                                  8-10 minutes

                                  Doughnuts                                                                                4-5 minutes

                                  fruit fritters                                                                                3 minutes                 

185 °C                       potato chips(finishing)                                                                 2-3 minutes

                                  cuts of fish                                                                                4-5 minutes

195 °C                       whitebait                                                                                    2-3 minutes


pour water on a fire involving oil/fat—use a fire blanket instead

1.3.3. Bakıng

This term usually refers to the dry oven cooking of flour products, but can also refer to such items as potatoes and apples. Vegetables and fruit are easy to bake and require less attention than flour-based products, such as cake, for which is important to understand the principles involved with each recipe-its balance, timing, correct temperature and effects of heat upon the product. A fan-assisted oven has a constant heat throughout its interior, and makes the art of baking much simpler.


Temperatures for baking:

Temperature                                                 °(C) Regulo                                   Foods

110-20                                                                    s                       meringues warming plates

140                                                                         1                        rich fruit cakes

150                                                                         2                        milk puddings

160                                                                         3                       casserols

180                                                                         4                       shortpaste, fish

190                                                                         5                       cakes

200                                                                         6                       chouxpaste, roast

220                                                                         7                       bread, puffpaste

230                                                                         8                       Yorkshire, scones

250                                                                         9                       browning


Note: Before placing food in the oven, always pre-heat the oven to the correct temperature.

Apart from making food digestible, baking creates appeal by giving foods color and

texture. Occasionally foods (e.g.bread) require a steamy condition when baking; if there isn’t

enough moisture in the product, a water bath can be placed at the bottom of the oven for best

results. To avoid the hazard of becoming too hot and spoiling the food within them ( as

would occur with cream caramels) it is customary to use a water bath (bain-marie) around

the vessel to lessen its temperature.

1.3.4. Roastıng

This used to be carried out on a ‘spit’ over an open fire but refers generally to the cooking of meat or vegetables in the oven in the presence of fat for basting. Radiated heat in the oven cooks the

surface of the food and conducted heat from the tray cooks the item from underneath. It very important to ensure that an even balance of heat is applied, according to the type of food, so that in cases where

contact with the tray would cause food to cook too quickly, a trivet is used to hold it up. This

would be necessary, for example, when roasting a best end joint of lamb, but not when

roasting potatoes, for which a crispy (well-cooked) finish is desired. The fat or oil present when oven roasting can be used for basting the food to prevent it from drying out. It is also responsible for developing a specific taste, according to the type of fat used, although many foods have their own proportion of fat and so shouldn’t require much added. Seasoning prior to roasting is also an important point to remember in most foods, but this may delay the coloring of meat, which may be avoided by seasoning after the initial sealing of the meat. Care must be taken when slow roasting that flavors typical of roasting are not lost through developing a steamy atmosphere within the oven. Occasionally it may be necessary to cover foods ( e.g. tougher quality meats ) with tin foil when lengthening the cooking time, so that moisture is not lost. However, it is important to open the foil near the end of cooking time to develop characteristic flavors. Any cooking liquors lost from the joint may be used in

accompanying sauces.Cooking times and oven temperatures will vary according to the foods being cooked.Remember that once removed from the oven a joint of meat will continue to cook as it cools

down, so a resting time is necessary before carving. Using a meat probe or thermometer

stuck into the thickest part of a joint will give an internal temperature for the meat and show

when it has reached cooking point.Vegetables (potatoes, onions, parsnips and turnips can all be roasted) may be parboiled before roasting.

Temperatures for roasting:

Meat                      Suitable joint                   Timingº  Suggested temperature

Beef              fore rib,rump,sirloin                     20min./500g+20min.                   200-225°

Lamp             best end, loin, leg,shoulder           25min./500g+20min.                   200-225°

Pork               all joint cuts                                 35min./500g+35min.                    200-225°

Poultry          Whole or joints                             20min./500g+20min.                   200°


2.4. Wet Cookery Process

2.4.1. Boılıng

The boiling point of water is 100°C. Foods cooked by this method are fully immersed

in water and brought to a rapid boil. Sometimes, as in the cooking of leafy vegetables, the

temperature is reduced a little but the water is still ‘moving’ at a rapid simmer. As a rule, the

foods cooked by boiling are those that will not be spoilt by the movement of the water and

where a moist result is desired.Suitable foods for boiling potatoes root vegetables

leafy vegetables pulses tough cuts of meat ham and gammon eggs pasta and rice

shellfish stocks The length of time that foods will require to be boiled will vary considerably with the

type and the preparation, but it must be remembered to ensure that all pieces of food are the

same size so that they are cooked at the same time. It is also an important point that foods

that require different cooking times must not be mixed, e.g. potatoes and Swede, as the

potato will become soft and even disintegrates before the Swede is cooked.

It may be necessary to use a lid during boiling to ensure that foods do not boil dry.

When using a lid, check occasionally that the moisture level is retained.

Boiling from cold

Some foods are placed in cold water, and then the temperature brought up to boiling

point. Stocks are an example of this: at the initial boil impurities rise and it is important to

refresh in cold water and re-boil to ensure a clear liquid. Starting the cooking process with

cold water is also safer when cooking large quantities. Unfortunately, nutrients can be lost in

the lengthened cooking time unless the cooking liquor can be used in accompanying sauces.

Boiling from 100’C

Many foods are plunged into already boiling water, the advantage and

disadvantage of this method are given below.


Advantages                                                                     Disadvantages


Retains nutrients                                                           more dangerous

Retains colour, texture                                                  must judge size of pan

Reduced cooking time                                                   temporary reduction of temperature

Cooking times more accurate                                        more care required at start

Coagulates proteins quickly





When plunging food into already boiling water it must be remembered to use a sufficiently large vessel to accommodate it all and to place it in carefully to avoid scalding splashes.

The fast boiling of some pulses for a minimum of 10 minutes is very important to

remove toxins present in their skin. This can only be done by boiling as the method of heat

distribution is constant and the temperature is high enough.

1.4.2. Braısıng

This is the cooking in the oven or on the stove but with a lower temperature and the

addition of moisture to approximately cover the food. It is a prolonged method of cookery;

tougher foods are cooked in this way. Often a bed of vegetables is placed in the vessel first to

prevent the protein food from coming into contact with the container, as this contact may

cause the food to become dry and tough. A well-fitting lid must be employed to maintain the

moisture level and create a steamy atmosphere whilst the liquid simmers so the food is both

stewed and steamed. Flavors and nutrients leach into the cooking liquor so this must be used

for an accompanying sauce.

The cooking liquor may consist of any or a combination of: water; stock; wine; beer.

Foods may be cut into portions or left as whole joints or pieces which will have an

effect on the length of the cooking time. However, it can be said that braising can take a few

hours for larger pieces.


Suitable foods for braising

Tougher cuts of meat such as brisket of beef, venison


Breast of lamb

Whole poultry

Game birds

Offal such as hearts and liver

Vegetables such as potatoes, celery, onions and cabbage

1.4.3. Poachıng

This method of cookery is often confused with boiling, but the difference is that the

temperature of the cooking liquor is held at a slow simmer and the food is not always

immersed in the liquid. Although foods cooked by poaching retain their shape, they do not

take on any interesting color and so could be looked on as unappetizing. Thus the importance

of a sauce made from the liquor, which not only retains the nutrients but also adds color and

interest to the finished dish.

As delicate foods are more easily digested and poaching does not require the addition

of fat, menus for invalids often incorporate poached dishes.

Generally poaching is used for delicate foods which may be damaged by a faster



Foods suitable for poaching

fish fillets

fish steaks



chicken breasts


There are two types of poaching: shallow or slow poaching and deep poaching.

a) Shallow or slow poaching

In this method, used for example in poaching plaice fillets, the liquid level is held to a

minimum and a cartouche or lid is used to trap steam, by which the food is also cooked. The

liquid can be water, wine, milk or stock, or combination of these, and may be flavored, for

example with finely cut onions and herbs. Cooking time is very short, either on the stove top

or in a moderate oven; the food is then drained and sauce made, using the cooking liquor.

b) Deep poaching

In this method the food (for example, whole salmon or a joint of ham) is completely

immersed in the cooking liquor. To avoid loss of taste it is important to poach in a wellflavored

liquor, using herbs, vegetables and seasoning. The cooking liquor is not often used

for sauce as there are large amounts of it and in the case of ham it will be very salty.

When deep poaching eggs the addition of an acid (e.g.vinegar) to the water helps to

speed up the coagulation of the protein so as to avoid the dispersal of the egg in the water.

However, it is equally important that the eggs used should be as fresh as possible.

Poached eggs can be prepared in advance of service, trimmed to shape and held in

iced water until they are required. A moment’s re-dipping in hot water will soon bring them

to the required temperature.

1.4.4. Steamıng

In this method of cookery, food is held on shelves and

surrounded by steam rising from boiling water in the bottom of the chamber. The steam

offers a moist cooking environment that has various advantages:

Ø food is unlikely to be overdone

Ø apart from watching water levels occasionally foods can be left unattened

Ø nutrients are not lost as the food does not come into contact with moisture directly.

One disadvantage however, is the fact that in the cooking process no colour is

added to the food and it may look unappetising. For this reason, sauces are often served with

steamed foods.


Foods suitable for steaming

potatoes and vegetables

fish portions

sponge puddings, including Christmas pudding


Foods that are likely to be spoilt by the steam must be protected during the cooking

process. For example, sponge pudding basins are covered with greaseproof paper and foil to

keep the steam out.

A steamer is normally referred to as an ‘atmospheric steamer’ to distinguish it from

the ‘pressure steamer’ in which steam builds up a pressure and so increase the temperature of

the chamber and the speed of cooking.

An important point to remember when using a steamer is to use the door as a guard

against a sudden rush of steam when the chamber is opened. Wait a few moments with the

door ajar to allow excess steam to escape upwards before fully opening the door. In using

pressure steamers, ensure that the temperature and so the pressure is lowered.

1.4.5. Mıcrowavıng

Really a combination of different methods of cookery according to its use, micro

waving is becoming increasingly important in catering establishments for its convenience

and speed although it still does have limitations due to the size of the chamber.

The oven works by creating waves similar to radio waves but of a different frequency.

These waves cause moisture molecules in foods to be agitated, creating friction and resulting

in heat (very much like you rub your hands together to make icy ham warm). Such high

temperatures are reached that the food continues to cook even after the cooking period and

so a resting time is often advised before service. Some microwaves are now available

combined with a convection oven facility as well as the microwave. This does have some

advantages but generally speed is the reason for choosing to use a microwave, and the

combined method may well slow the process down again.


Suitable foods for microwaving

poached fish

quick jacket potatoes

boiling of root and pulse vegetables

casserols (limited number of portions)


reheating portions and complete meals

‘steamed’ sponge puddings

One of the biggest advantages of using a microwave oven is that very little energy is

used in its operation—it is thus very economic. It is a boon for fast food establishments and

for cooking to order and reheating foods. A variety of foods may be cooked by microwave

but it is important to recognize some of the possible disadvantages:

Ø drying can occur due to overcooking

Ø certain items explode in the oven, e.g. eggs in their shells.

Ø fruits and dryed fruit products can become dangerously hot an deven flame

Ø protein foods do not colour, e.g. chicken, will be cooked but without being golden

brown and crispy.






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