Biologically active properties of hydrolysed and fermented milk proteins

Abstract

A comparative analysis of protein and peptide profile, biological activities of hydrolysed bovine colostrum and whey was performed. It was found that the depth of proteolysis, qualitative and quantitative composition of protein component of samples determined the level of their antiradical, antimutagenic, antimicrobial and antigenic properties. SDS-electrophoresis of experimental samples revealed more extensive protein hydrolysis in the course of alcalase treatment than during enzymatic reaction with neutrase. Using fluorimetric method the influence of hydrolysis with endopeptidases and fermentation with Lactobacillus acidophilus on antioxidant properties of milk proteins was established. 1.7-5.5 times increase in antiradical activity of derived samples in comparison with native proteins was recorded. Reduction in mutation rate induced by whey hydrolysate in tested strain Salmonella typhimurium TA 98 ranged from 15.7 % to 49.2 %, whereas antimutagenic effect on strain TA 100 varied from 18.8 % to 52.1 %, exceeding the similar values shown by colostrum hydrolysates. Samples of colostrum and whey hydrolysed with alcalase are enriched with specific short-chain peptides which determine their relatively high antimutagenic and antiradical properties. Immunoprecipitation reaction demonstrated effective splitting of β-lactoglobulin by alcalase, resulting in production of hypoallergenic hydrolysates. It was found by impedimetric technique that neutrase-cleaved colostrum accounted for maximum inhibition of Escherichia coli ATSS 8739 (82 %) and Staphylococcus aureus ATSS 6538 (19 %). Samples of enzymatic hydrolysates of colostrum and whey proteins with confirmed antimicrobial, antimutagenic and antioxidant action were obtained. The use of hydrolysed and fermented colostrum with elevated antioxidant potential in special nutrition appears extremely promising.