[Chromatographic analysis on tryptic hydrolysis of whole casein]

Tryptic hydrolysis of whole casein was investigated by high performance size exclusion chromatography (HPSEC) in combination with the degree of hydrolysis (DH). In terms of HPSEC chromatograms obtained at different DH values, the complex process of enzymatic reaction and the relative molecular mass distribution of multiple hydrolysates were quantitatively characterized. Based on the information of casein micelle structure, the possible reaction mechanism was deduced from a series of chromatograms. Being taken into account the primary structure of whole casein and the target amino acid of trypsin, the distribution of theoretical peptides were accurately calculated by determining the split sites of complete enzymatic hydrolysis. According to the relationship between retention time and relative molecular mass, the corresponding HPSEC absorption peaks of active peptides in hydrolysates were identified, and caseinophosphopeptides sequences were also characterized.