Enzymatic hydrolysates of whey protein and chicken egg ppotein: production, physical-chemical and immunochemical characteristics

Abstract

Whey protein concentrate (WPC) and chicken egg protein (CEP) and enzymes such as pancreatin and alkalase have been used. Proteolysis of proteins was carried out in an FA-10 fermenter for 3 hours at an enzyme : substrate ratio of 1:50 in dry matter, at optimal pH and temperature for pancreatin and alkalase. Enzymes were inactivated at +75 °C and fermentolizate was ultrafiltered. The solutions were concentrated by reverse osmosis and freeze-dried. The molecular weight distribution of the peptide fractions was evaluated by HPLC. Residual antigenicity was determined by the method of indirect enzyme-linked immunosorbent assay and expressed as the fold of antigenicity reduction relative to the original protein. During WPC proteolysis with pancreatin the hydrolyzate was obtained with a fold reduction of antigenicity of 2.3×103 relative to the initial WPC. A decrease in antigenicity of 4.7×104 times was achieved with proteolysis of WPC by alkalase. The combination of WPC fermentolysis with pancreatin or alkalase followed by ultrafiltration reduced the content of high molecular weight peptides with a mass more than 8.7 kDa. The multiplicity of decrease in antigenicity with respect to the starting protein was 1.64×105 and 1.90×105, respectively. After repeated ultrafiltration the reduction in antigenicity of the obtained WPC alkalase or pancreatin hydrolysate was more than 1.0×106 and more than 5.0×105, respectively. The decrease in antigenicity of the CEP hydrolyzate obtained with proteolysis by alkalase and ultrafiltration compared to the initial CEP was 1.0×105 times, and 5.0×105 times when we used repeated ultrafiltration. A significant decrease in the content of high molecular weight peptides and a decrease in the antigenicity of peptide mixtures based on WPC and CEP to the values that permit their use in hypoallergenic products is achieved by combining proteolysis and double ultrafiltration through a UF10 membrane.