Determination of biologically active substances in protein-berry concentrates

Abstract

Protein Berry Coagulation Polyphenols Amino acid Abstract Introduction. Research of the polyphenolic compounds and amino acid composition of proteins, including the content of free and bound amino acids, in protein-berry concentrates (PBC), obtained by thermo acid coagulation are an actual direction. Materials and methods. Protein-berry concentrates were obtained by thermo acid coagulation of milk proteins using blackcurrant paste as a coagulant, which is a source of biologically active substances – vitamins, minerals, polyphenols and others. Amino acid composition and polyphenolic compounds were determined by high performance liquid chromatography followed by the identification of individual compounds in the studied extracts of protein-berry concentrates. Results and discussion. The research results of polyphenol composition were analyzed compared with the control (blackcurrant paste) and the degree of their transition to protein-berry concentrates was determined, which is about 55.31 % of polyphenols, including anthocyanins. Proteins in concentrates have a full amino acid composition and contain all essential amino acids, the content of which from amount is 41.97 % and 43.96 %, respectively, for protein-berry and milk-protein. A quantitative content of 18 free amino acids and 16 bound amino acids has determined in protein-berry and milk-protein concentrates, of which glutamic acid, histidine, methionine, leucine and proline are dominated. The nonessential amino acids were determined, the content of which is 58.03 % and 56.04 % from the sum of total amino acids in the PBC and MPC (control). The content of essential amino acids in protein-berry concentrate has increased by 14.75 % and the nonessential amino acids by 24.45 % by the following amino acids: threonine at 0.156 mg%, lysine at 0.21 mg%, tryptophan at 0.221 mg%, phenylalanine at 0.525 mg% compared with the control sample. Conclusions. The protein-berry concentrates had a polyphenolic compound content of 331.86 mg / 100 g, which characterizes their natural violet color. The amino acid composition in PBC has increased by 20.18 % compared with the classic milk-protein concentrate, as a result of complex coagulation of casein and whey proteins. Article history: