CALORIC CONTENT

From Big Medical Encyclopedia

CALORIC CONTENT (Latin calor heat, heat) — the energy value of foodstuff equal to amount of the energy which is released at oxidation of feedstuffs in an organism. To. it is expressed in calories or kilocalories (1 kcal = 1000 kcal or is equivalent to 4,187.103 J).

Calculation on To. it is used at comparative assessment of foodstuff, planning of food, by drawing up diets (see. Diet ).

Need of the person for energy is defined by his physiological condition, intensity of work and level of a muscular exercise, sports activities, the nature of homework, climatic conditions etc.

In an organism feedstuffs are oxidized with an expenditure of oxygen and with formation of carbon dioxide gas and water. About the energy released in an organism it is possible to judge by amount of absorbed oxygen and the emitted carbonic acid. Size K. is defined by availability of unoxidized carbon atoms and hydrogen in feedstuffs. At combustion of the main feedstuffs in the special device (a calorimetric bomb) the following amounts of heat are distinguished: at combustion of 1 g of fat — 9,3 kcal, monosaccharides — 3,75 kcal, proteins — 4,0 kcal. Since an end product of exchange of proteins is urea, it is necessary to make allowance for the size of warmth of its combustion therefore the actual heat of combustion of proteins is equal in an organism to 4,1 kcal. The sizes reflecting To. 1 g of feedstuff at its combustion in an organism, are called coefficients of caloric content, or caloric coefficients.

In certain cases at calculations To. an edible part of foodstuff (so-called physiological caloric content) consider that average comprehensibility of proteins is equal in diets to 84,5%, fat — 94%, carbohydrates — 95,6%. In other cases use more detailed data on comprehensibility of feedstuffs at consumption of separate products (tab. 1).

During the definition To. foodstuff which before inclusion in food is exposed to technological and culinary processing it is necessary to consider the losses arising in the form of waste (a bone, a sinew during the processing of meat, fish, a peel during the processing of vegetables and potatoes etc.).

It is possible to determine the caloric content of food physical., chemical and calculation methods.

Principle physical. a method consists that after special preparation the hinge plate of the studied product is burned and define the exotherm corresponding to the caloric content of the burned hinge plate. From this draw a conclusion about the caloric value of the studied product.

The principle of a chemical method of definition To. comes down to determination of quantitative content in food of proteins, fats, carbohydrates and to calculation by means of caloric coefficients To. the studied food. Defined thus To. represents gross To. edible part of a product; for definition net To. it is necessary to consider the coefficient of comprehensibility specified in table 1. Accepting average comprehensibility of equal 90%, subtract from caloric content gross 10%. In laboratory practice for determination of caloric value of foodstuff and dishes are sometimes limited to definition only of fats, proteins and ashes. Carbohydrates determine by a calculation method.

At a calculation method of definition To. food and separate products use special tables. To. some foodstuff it is provided in table 2.


Table 1. COEFFICIENTS of COMPREHENSIBILITY of VARIOUS PRODUCTS AT the MIXED FOOD


Table 2. CONTENT of the MAIN FEEDSTUFFS AND ENERGY VALUE of SOME PRODUCTS (in terms of 100 g of an edible part)




Bibliography: Burstein A. I. Methods of a research of foodstuff, Kiev, 1963, bibliogr.; Hygiene of food, under the editorship of. K. S. Petrovsky, t. 1 — 2, M., 197.1; Clinical nutrition, under the editorship of I. S. Savo-shchenko, M., 1971; Tables of chemical composition and nutritional value of foodstuff, under the editorship of F. E. Budagyan, M., 1961; Chemical composition of foodstuff, under the editorship of A. A. Pokrovsky, M., 1976.

V. A. Kudasheva.

Яндекс.Метрика