Effect of different protease on the hydrolysis degree and antigenicity of cow milk protein

Abstract Cow milk protein (CMP) has high nutritional value and is a common food additive, but its allergenicity has raised concerns. In this study, we investigated whey protein and casein hydrolysis as a potential method of lowering CMP antigenicity. We tested three endo-type proteases (neutral protease, papain, trypsin) and one exo-type protease (flavourzyme). We applied response surface methodology to obtain optimized conditions for each enzyme, decreasing antigenicity by >75 %. Maximum hydrolysis of whey protein and casein was achieved with a combination of proteases (1:1.5 papain to flavourzyme, 1:2 and 1:1.5 neutral to flavourzyme in whey protein and casein, respectively). Antigenicity rates declined by 85–92 % across all treatments. The proportion of small-molecular-weight components in enzymatic hydrolysate rose 87–90 %, indicating low antigenicity. Experiments using protein hydrolysates and in vitro simulated digestion tracts revealed decreasing antigenicity as digestion proceeded. Our findings have important implications for the development of hypoallergenic milk products.