Comparison of products of whey proteins concentrate proteolysis, obtained by different proteolytic preparations

Abstract

An important source of bioactive peptides is hydrolyzed products based on milk whey: hypoallergenic products, hydrolyzates for baby food, and products for athletes. However, in their production, proteolytic preparations of different origin are used. This may affect the degree of proteolysis of the biologically active peptides (BAP) proteins-precursors, the proteolysis products molecular weight distribution and, accordingly, the probability of BAP formation. A comparison of the degree of whey protein concentrate (WPC) proteins proteolysis and the molecular weight distribution of proteolysis products obtained by the action of proteolytic preparations of animal, plant and microbiological origin has been carried out. The following enzyme preparations were used for proteolysis: papain, neutral protease, trypsin, chymotrypsin and pancreatin. WPC was used as the substrate. The proteins fractional composition and the molecular weight distribution of proteins and peptides were characterized in it before the proteolysis. Proteolysis of 15 % WPC solution was carried out at a temperature of 37°C, pH 7.9 and enzyme: substrate ratio 1:20. During proteolysis, samples were periodically taken off for spectrophotometric determination of proteolysis products soluble in 5 % trichloroacetic acid (TCA). Molecular weight distribution of the resulting polypeptides and peptides was established by gel filtration of the reaction mixture after deposition of the unsplit proteins in 5 % TCA. As a result of the research, it was found that the majority of proteolysis products were formed during the first 30–60 minutes. Proteolysis was mostly completed by 120 minutes. Gel filtration on Sephadex G-50 showed that hydrolysates differ by molecular weight distribution. The highest amount of low molecular weight peptides (M<1,500 Da) was obtained by the action of neutral protease (29 %) and pancreatin (25 %). The main precursor of BAP – β-lactoglobulin, according to the results of electrophoresis, showed the highest sensitivity to the action of neutral protease (79 %), pancreatin (81 %) and trypsin (71 %)