EFFECT OF COOKING

The effect of cooking upon the three chief constituents of food proteins, carbohydrates and fats-is visible in their increased digestibility.

PROTEINS

The protein of meat (myosin), of egg (albumen), of wheat (gluten), of pulse (legumin) is coagulated by heat. Avoid high temperatures as the protein hardens, denatures and shrinks and the food becomes indigestible. The connective tissue is converted into gelatine which is soluble in water and rendered digestible. The proteins' biological value is improved by moderate heating.

CARBOHYDRATES

STARCH in food is greatly affected by heat. By moist heat, it is converted first into a soluble form and then by extreme heat into a new substance, sweetish in flavour-dextrin as in the crust of bread. Moist heat causes the starch grains to swell; it gelatinizes at a temperature below boiling point of water, the degree of heat varying with the kind of starchy food.

CELLULOSE is softened by the application of moist heat.

SUGAR when heated in water dissolves, then colors, upon further heating, turns brown and becomes a caramel and emits a lovely flavour, but does not crystallize. Moderate heat does not cause much loss of mineral salts and vitamins, except vitamin C.

FATS

1. If heated to a very high degree for a long time, fats undergo partial decomposition and fatty acids and glycerol are produced. Glycerol further decomposes into acerolin which is an irritating compound to the digestive system.

2. Cooking pleases the eye and is receptive to the palate and helps to stimulate the digestive juices, thereby creating an appetite. On application of heat, the red coloring matter such as hemoglobin in meat decomposes and changes the red colour to brown. Flavors are developed, which stimulate the digestive juices. The colour of the vegetables is brightened. Green vegetables fast boiled without a lid, improve the green colour. Cauliflower when boiled, in acidic medium, gets a white refreshed look.

3. Cooking sterilizes the food partially. Cooked food can be stored for a longer time and it prevents food poisoning and diseases when stored properly. Some of the diseases producing germs are killed by cooking. They are killed because of high temperature during the cooking process. A temperature of 60° (140°F) applied over 30 or more minutes, kills most of the pathogenic germs, however, there are some spore germs which are not destroyed by the usual cooking temperature: they take about 4 to 5 hours to get destroyed at a high temperature. High temperature penetrates to the centre or interior of food, especially in pork, beef and mutton.

4. Cooking retains, as far as possible, the nutritive and flavoring ingredients. The flavour depends upon the amount and kind of extractives present, and the acids developed. Nutritive value is enhanced if the fat proportion in the meat is more. While cooking, the nutrition could be preserved by using the cooking liquor.

5. Cooking gives a variety to the menu, as one food item could be cooked in various ways and given different textures, e.g. mutton in a soup, roast joint, croquettes. Stews, steaks, keema, sookha meat, boti kababs etc. Different methods of cooking when used make the menu interesting and enhance variety. It is. Therefore, easier to plan a balanced diet.

6. Cooking preserves food for a longer time. The high temperature destroys bacteria and limits spoilage.