BIOLOGICAL VALUE OF PROTEINS OF MILK OF SIMMENTAL COWS PRODUCED UNDER CONDITIONS OF INTENSIVE TECHNOLOGY

Taking into account modern requirements, the biological value of the protein component of the Simmental breed Krov milk produced under intensive technology has been studied. The amino acid composition of milk proteins was identified by high-performance liquid chromatography. To analyze the biological value of proteins, calculated indicators were used: the amino acid index and the amino acid number (skor) of essential amino acids, taking into account the true digestibility of each of them. As a result of the research, all the essential and interchangeable amino acids and a fairly high concentration of many of them were identified. Among the essential amino acids, the largest amount in the milk samples contained phenylalanine+tyrosine, leucine, lysine, valine, and the smallest-tryptophan, methionine+cysteine. In the aggregate of interchangeable amino acids, the highest saturation was noted for glutamic acid+glutamine, arginine, proline, and the lowest-glycine, alanine. The predominance of interchangeable amino acids was noted in the protein component, which caused a low amino acid index (0.61). The amount of assimilated essential amino acids was higher relative to the reference protein. However, the amino acid score had a wide oscillation amplitude: from 149.6 % for the amino acids phenylalanine + tyrosine to 61.2 and 87.8 %, respectively, for tryptophan and methionine+cysteine, which indicated their imbalance. The essential amino acids tryptophan and methionine+cysteine were limiting, since their amino acid number (skor) is below 100 %.