ANALYSIS OF PROTEIN HYDROLYSATES .1. USE OF POLY(2-HYDROXYETHYLASPARTAMIDE)-SILICA COLUMN IN SIZE-EXCLUSION CHROMATOGRAPHY FOR THE FRACTIONATION OF CASEIN HYDROLYSATES

A poly(2-hydroxyethylaspartamide)-silica column (PHEA), with a 0.05 M formic acid mobile phase, was tested for the size exclusion chromatography (SEC) of amino acids and small peptides (molecular mass lower than 1000 Da). The PHEA shows good SEC properties, although some nonideal size exclusion behavior suggests it has a low cationic character. On the other hand, the separation of peptides is affected by the sample salt concentration. The technique was applied to the analysis of several casein hydrolysates, and the mean chain length of peptides in the collected fractions indicates a good separation of peptides on the basis of their size.