Physicochemical characteristics and antigenicity of whey protein hydrolysates obtained with and without pH control

Protein hydrolysis on a laboratory scale is commonly carried out under controlled pH conditions, while, in industry, it is conducted without pH control. The impact of pH, with or without control, substrate concentration (S%) and enzyme-substrate ratios (E/S) on physicochemical and antigenic characteristics of whey protein hydrolysed with Alcalase were assessed. S% and E/S affected the degree of hydrolysis; pH conditions resulted in hydrolysates with different physicochemical characteristics and concentrations of β-lactoglobulin and α-lactalbumin. Although pH plays a crucial role in the hydrolysate characteristics due to its influence on the enzyme cleavage pattern, the responses of anti-β-lactoglobulin, anti-α-lactalbumin IgE and IgG to hydrolysates were similar and independent of pH control. In the absence of control, pH increased response to anti-BSA antibodies. Overall, hydrolysis with Alcalase resulted in different peptide compositions, presenting possibly different bioactivities, but the cleavage of β-lactoglobulin and α-lactalbumin epitopes did not change.