Effects of pH, temperature and enzyme-to-substrate ratio on the antigenicity of whey protein hydrolysates prepared by Alcalase

Response surface methodology was used to study the effects of pH (7.0–11.0), temperature (30–60 °C), and enzyme-to-substrate ratio (4000–8000 units g−1 protein) on the residual antigenicity of whey protein concentrate (WPC, 77.5% protein) hydrolysates obtained with Alcalase. It was shown that enzymatic hydrolysis with Alcalase could reduce the antigenicity of WPC for α-lactalbumin (α-LA) and β-lactoglobulin (β-LG) effectively and the reduction of antigenicity could be controlled by regulation of three independent variables (pH, temperature, enzyme-to-substrate ratio). Models for anti-α-LA and anti-β-LG IgG binding inhibition were established. Temperature had the greatest effect on the anti-α-LA IgG binding inhibition and pH had the greatest effect on the anti-β-LG IgG binding inhibition. Enzyme-to-substrate ratio influenced inhibition for α-LA and β-LG to a lesser extent. The anti-α-LA IgG binding inhibition was significantly negative related with the degree of hydrolysis (DH), while the anti-β-LG binding inhibition was not related with the DH.