Reversed phase and size exclusion chromatography of milk protein hydrolysates: relation between elution from reversed phase column and apparent molecular weight distribution

Hydrolysates of casein and whey protein were analysed with size exclusion and reversed phase chromatography. Hydrolysate elution patterns obtained from the two chromatographic techniques were correlated. The apparent molecular weight distribution (MWD) of the peptide mixtures could be predicted accurately from their reversed phase chromatograms, using partial least squares regression. Reversed phase profiles of specific molecular weight fractions overlapped considerably, indicating that the relation between reversed phase chromatography and MWD is complex. Retention times of defined casein peptides on reversed phase column were predicted by summing retention time coefficients of the constituent amino acids. The coefficients were calculated by linear regression from a data set of peptide sequences and retention times obtained from LC/MS analysis of casein hydrolysates. The newly calculated retention time coefficients resulted in better prediction of retention time of casein peptides than did prediction with coefficients from literature. (C) 2001 Elsevier Science Ltd. All rights reserved.