Fats organic compounds included in composition of plant and animal tissues and consisting mainly of triglycerides (esters of glycerol and various fatty acids). Fats and fat-like substance made to unify the title of lipids (see).
Most fat is found in subcutaneous adipose tissue, as well as in the seal. A certain amount of fat contains muscle tissue, bone marrow, liver (especially in fish). Fat are an important component of milk. In plants fat accumulates mainly in fruits and seeds. The fat content in oil-bearing seeds, such as sunflower seeds, reaches 40% (dry substance).
Physical-chemical, chemical and biological properties of fat depend on the content of those or other fatty acids. They affect such indicators as the melting temperature, density, refractive index, iodine number, etc. Fatty acids are saturated and unsaturated. Neutral fats containing saturated acids at room temperature are in the solid state. Neutral fats with unsaturated fatty acids at room temperature liquid.
Fats are the basic food substances; by their calorie fats exceed proteins and carbohydrates more than 2 times. Their value is determined mainly by the content of unsaturated fatty acids, phosphatides, choline, vitamins A, D, E, so in the diet is necessary to have a complex animal and vegetable fats. The absorption of fats in the largely determined by the temperature of melting them. Refractory fats (melting temperature above 37 degrees) absorbed worse than vegetable oil, butter, goose and duck fat (melting point below 37 degrees). In the composition of animal fats contain cholesterol (see). In vegetable oils are unsaturated fatty acids (linoleic, linolenic, arachidonic), which play an important role in metabolism (in particular, cholesterol) and are indispensable factors feeding and phosphatides (see), with lipotropic action. Fat milk, cod liver oil, sea bass contain a significant amount of vitamin a, And in vegetable oils, vitamin E (see table).
To compound types of fats are margarine and cooking fats. Raw materials for preparation of the combined fats are used vegetable oil, whale or fish oil, translated into solid state special treatment with hydrogen (hydrogenation). Margarine is prepared by emulsification of TRANS fat milk, cream or water, adding vitamins, gums, dyes, and other components. Highest grade margarine butter, spreads) are full substitute for butter. Other varieties are consumed mostly by cooking food.
Daily needs adult in fats is 80-120 g (depending on the severity of work, sex, age), and 30% should fall on the share of vegetable oils. In old age fat intake is recommended to be reduced to 60-70 grams per day.
When storing food fats in them there are chemical changes that result in lower nutritional value and the deterioration of their taste qualities: hydrolysis (splitting glycerides into its parts), rancid or oxidation (reaction of interaction of glycerides, fatty acids with oxygen and the formation of corrosion products) and polymerization (consolidation of molecules).
For the prevention of damage fats should be maintained at a low temperature in the dark and in a sealed container.