Extensive hydrolysis of milk protein and its peptidomic antigenicity analysis by LC-MS/MS

Milk protein concentrate (MPC) is considered an ideal substitute of cow milk because of its similar protein and nutrition. In this study, MPC was hydrolyzed to peptides by alcalase and neutrase, and the properties of hydrolysate were evaluated. When MPC was hydrolyzed at the ratio of alcalase and neutrase of 1:1 and enzyme to substrate ratio of 6000 U/g MPC at 50°C, pH 8.5 for 3 h, the proportion of peptides with molecular weights <1 kDa was 85.31%, and the antigenicity reduction rates of casein and β-lactoglobulin were 33.76% and 22.38%, respectively. Moreover, LC-MS/MS peptide identification revealed that the alcalase and neutrase disrupted a total of 65 epitopes of casein and 21 epitopes of whey protein, which further elucidated the mechanism of complex enzyme hydrolysis to reduce milk protein allergenicity.