Abstract: The enzymatic hydrolysates of casein are so complicated that there has no effective method for quantitative analysis. On the basis of membrane separation and high performance size exclusion chromatography (HPSEC), standard peptides with different relative molecular mass ranges were prepared, and the linear relationships between mass concentration of the standard peptides and the corresponding peak areas were established. Consequently, mass concentration of the different hydrolysates at different reaction time can be accurately calculated. The combination of chromatography and membrane separation is of great importance to the quantitative analysis of the complicated hydrolysates, which can be also applied to the other macromolecular systems, such as carbohydrates.

Key words: complicated system, enzymatic hydrolysis, high performance size exclusion chromatography, membrane separation, quantitative analysis , casein