[Biological and nutritional value of food products]

The paper deals with a detailed analysis into the methods of study and of the validity of terminology adopted in denoting the usefulness of food products, proceeding from their chemical composition. The author proposes to distinctly subdivide the notions of the alimentary, biological and energy producing values, but unite them under a general term reflecting the totality of the useful qualities of the products that covers the estimation therein of a broad range of nutrients, which should be referred to as "nutritional value". The terms of biological and energy producing values are special designations. The first of them reflects the quality of proteinic components in the product which have to do both with the digestability of the protein and with the degree to which its amino acids compositions is balanced. Then it should be borne in mind that the indices of biological value may undergo substantial changes, both under the effect of rigid methods of technological treatment, that brings about a change in the structure of the protein molecules proper, and consequent upon their interaction with other nutrients, as well as during their long-term storage. An important advantage that offers the determination of the biological value indices is an analytical segregation from among numerous biological properties the ones which are related to the features specific for the structure precisely of the proteinic constituents of the food. The determination of this index allows it to differentiate the useful qualities of the protein from a great number of other factors that can significantly change the assimilation of the products by the organism, including the presence therein of extraneous substances. The term energy-producing value of the products characterizes the part of the energy that can be liberated from the nutrients in the course of biological oxidation and used in securing physiological functions of the organism. As a basis for expressing the alimentary (nutritional) value of the products a method of the integral score, reflecting the degree to which the chemical composition of the study product corresponds to the formula of balanced nutrition worked outhe author is suggested. The energy variant of the integral score presents definate advantages, for with it the author estimates the percentage of satisfied requirements of an adult person in nutrients with the consumption of products in an amount that corresponds to a definate portion of energy, 300 kcal, for example (which comprises roughly 10 per cent of an average diurnal requirement in energy). The energy variant of the score makes it possible to determine the "degree of completness" of the product's calories with essentian nutritional factors.