FOOD CONSTITUENTS

FOOD CONSTITUENTS
Food is composed of the following five constituents:
 Carbohydrates
 Fats
 Proteins
 Minerals
 Vitamins
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
and potato.
Fats:
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 include sauteing, stir-frying, and deep-frying. Commonly used fats and oils include butter,
olive oil, sunflower oil, lard, beef fat (both dripping and tallow), rapeseed oil or canola, and peanut oil. The inclusion of fats tends to add flavor to cooked food.


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.

Minerals:

Minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen which are present in common organic
molecules. Sometimes these "minerals" come from natural sources such as ground oyster shells. Sometimes minerals are added to the diet separately from food, such as mineral
supplements, the most famous being iodine in "iodized salt." Other minerals are calcium, chloride, magnesium, phosphorus, potassium, sodium and sulphur. These minerals are obtained from milk, other dairy products, cereals, legumes, bone meal, meat, fish, all fruits, vegetables, table & sea salt etc.

Vitamins:

Vitamins are essential for the normal growth and development. It is a key nutrient that the body needs in small amounts to grow and stay strong. Examples are vitamins A, C, and E. Vitamins are found in many fruits and vegetables; especially green peppers, citrus, strawberries, tomatoes, broccoli, leafy greens, potatoes, animal foods; such as liver, whole eggs and milk.

EFFECTS OF COOKING

The effect of cooking upon the food constituents are  discussed below:-

Action of Heat on Carbohydrates

The interaction of heat and carbohydrate is complex. Longchain 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 crystallisation is driven off, then caramelisation starts, with the sugar undergoing thermal decomposition with the formation of carbon and other breakdown products producing caramel. An emulsion of starch with fat or water can, when gently heated, provide thickening to the dish being cooked. In European cooking, a mixture of butter and flour called a roux is used to thicken liquids to make stews or sauces. In Asian cooking, a similar effect is obtained from a mixture of rice or corn starch and water. These
techniques rely on the properties of starches to create simpler mucilaginous saccharides during cooking, which causes the familiar thickening of sauces. This thickening will break down, however, under additional heat.

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.

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.

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.

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