Cooking is the act of preparing food. The term cooking encompasses all methods of food preparation including non-heated methods. It encompasses a vast range of methods, tools and combinations of ingredients to alter the flavour or digestibility of food. It is the process of selecting, measuring and combining of ingredients in an ordered procedure in an effort to achieve the desired result. Factors affecting the final outcome include the variability of ingredients, ambient conditions, tools, and the skill of the individual doing the actual cooking.
The diversity of cooking worldwide is a reflection of the myriad nutritional, aesthetic, agricultural, economic, cultural and religious considerations that impact upon it. Cooking often requires applying heat to a food, which usually, though not always, chemically transforms it, thus changing its flavour, texture, appearance, and nutritional properties. There is archaeological evidence of roasted foodstuffs, both animal and vegetable, in human (Homo erechts) campsites dating from the earliest known use of fire, some 800,000 years ago. Other methods of cooking that involve the boiling of liquid in a receptacle have been practiced at least since the 10th millennium BC, with the introduction of pottery
EFFECTS OF COOKING
Action of Heat on Proteins
When proteins are heated they become de-natured and change texture. In many cases, this causes the structure of the material to become softer or more friable meat becomes cooked. Cooking at ordinary temperatures renders protein foods more digestible. At high temperatures the protein itself gets denatured thus making it of nutritive value. In some cases, proteins can form more rigid structures, such as the coagulation of albumen in egg whites.
Proteins:
Edible animal material, including muscle, offal, milk and egg white, contains substantial amounts of protein. Almost all vegetable matter (in particular legumes and seeds) also includes proteins, although generally in smaller amounts. These may also be a source of essential amino acids. When proteins are heated they become de-natured and change texture. In many cases, this causes the structure of the material to become softer or more friable meat becomes cooked. In some cases, proteins can form more rigid structures, such as the coagulation of albumen in egg whites. The formation of a relatively rigid but flexible matrix from egg white provides an important component of much cake cookery, and also underpins many desserts based on meringue.
Liquids:
Cooking often involves liquids, both added in order to immerse the substances being cooked (typically water, stock or wine), and released from the foods themselves. Liquids are so important to cooking that the name of the cooking method used may be based on how the liquid is combined with the food, as in steaming, simmering, boiling, braising and blanching. Heating liquid in an open container results in rapidly increased evaporation, which concentrates the remaining flavours and ingredients this is a critical component of both stewing and sauce making.
Action of Heat on Fats
Fat melts when it comes in contact with heat. 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 caroling which is an irritating compound to the digestive system. When fat heated for long time at too slow temperature it thickens, becoming gummy. This condition is known as polymerization, and fat that has reached this stage is no longer fit for use.
Fat:
Fats and oils come from both animal and plant sources. In cooking, fats provide tastes and textures. When used as the principal cooking medium (rather than water), they also allow the cook access to a wide range of cooking temperatures. Common oil-cooking techniques includes sauteing, stir-frying, and deep-frying. Commonly used), Frapeseed oil include butler. includes sueflower oil, Jard, beef fat (both dripping and tallow), rapeseed oil or Canola, and peanut oil. The inclusion of fats tends to add flavour to cooked food, even though the taste of peanut oil. The includes often unpleasant. This fact has encouraged the popularity of high fat foods, many of which are classified as junk food such as hamburgers or convenience fried Cereal snacks. Prolonged heating or cooking at high temperature makes the fat rancid and foul smelling.
Action of Heat on Carbohydrates
The interaction of heat and carbohydrate is complex. Long chain sugars such as starch tend to break down into more simple sugars when cooked, while simple sugars can form syrups. If sugars are heated so that all water of crystallization is driven off, then caramelization starts, with the sugar undergoing thermal decomposition with the formation of carbon and other breakdown products producing caramel. Starch granules swell upon application of moist heat- gelatinization.
Carbohydrates:
Carbohydrates used in cooking include simple sugars such as glucose (from table sugar) and fructose (from fruit), and starches from sources such as cereal flour, rice, arrowroot, potato. The interaction of heat and carbohydrate is complex.
Action of Heat on Minerals
There is no appreciable loss of minerals due to cooking. Some minerals are made more readily available by cooking.
Action of Heat on Vitamins
There is some unavoidable loss of vitamins during cooking. The loss is considerable in respect of thiamine and vitamin C. Vitamin A and D are not destroyed by the ordinary methods of cooking. Vitamin B may be destroyed during cooking if cooked at high temperature. The use of baking soda in cooking causes further destruction of vitamins.
EFFECTS OF COOKING ON DIFFERENT TYPES OF INGREDIENTS
Cereals:
Rice is washed before cooking. Excessive washing removes the water-soluble vitamins and mineral. The proactive of cooking rice in large quantities of water and draining away the excess of water at the end of cooking leads to further loss of B-group vitamins and minerals.
Rice, therefore, must be cooked with just enough water so that all the water is absorbed at the end of cooking-this is usually 2 or 2½ times the volume of rice. All cereals (eg, water flour) absorb water and during cooking the starch granules swell up and burst. This renders the digestion of starch rapid and complete.
Pulses:
Pulses are rich in protein (20 to 25%). They also contain small quantities of starch. It is very important to boil pulses very thoroughly. This destroys the antitypic substance present in them. Undercooked starch is difficult to digest.
Green Leafy Vegetables:
Green leafy vegetables are prized for vitamins and minerals. The vitamin A which occurs in the form of thiamine and vitamin C are partially destroyed by the vitan
If the cooking water is drained away, there will be loss of not only vitamins but also minerals. It is therefore or the proper length green leafy vegetables should be cookeds but also minerals. of water and fore the shelf length of time. Baking soda should not be used to hasten Cooking but it will reduce the life.
Other Vegetables:
Vegetables like potatoes should be cooked with their outer skin intact, this retains all the Vitamins and minerals contained in them. As a rule, vegetables should be cooked in a small amount of water to prevent loss of vitamins and minerals. They can also be cooked by steaming.
Cooking of Fruits:
Most fruits are eaten fresh and raw. This makes the vitamins present in fruits easily available. Fruits can also be cooked by stewing, this will result in loss of some vitamins, particularly, vitamin C.
Cooking of Meat:
Meat is cooked in a number of ways. While cooking, meat coagulation of protein is at 60°C.
- There is reduction in water content; consequently there is shrinkage of meat,
- Collagen which is a protein of the connective tissues is changed into gelatin,
- Elastin, which is also component of connective tissue is not affected,
- The fat of meat melts,
- There is loss of mineral in cooking water but this water can be used as soup or gravy. • Loss of B-group vitamins especially thiamine.
Cooking of Fish:
Fish contains so little connective tissue, that the cooking time is very short. The proteins coagulate at 60°C.
Cooking of Milk:
When milk is heated, a scum consisting of fat, forms on the surface. This makes it difficult for steam to escape; hence milk boils over easily. Some of the lactalbumin sticks to the sides and bottom. Prolonged boiling alters the taste of milk. The cooked flavour is due to burning or caramelization of milk sugar. There is destruction of thiamine and vitamin C during boiling. Milk, which is already a poor source of vitamin C becomes poorer at the end of boiling. Boiling destroys enzymes and the useful lactic acid bacteria present in milk.
Cooking of Eggs:
The albumin of the egg begins to coagulate at 60°C; and solidifies at 64°C-65°C. At boiling point (100°C), the albumin becomes tough. However there is little change in the nutrients present in the egg.