Non-Size Exclusion Effects During Gel Permeation Chromatography of Milk Protein Hydrolysates on an FPLC Superose 12 Column

Abstract

Hydrophobic peptides and aromatic amino acids adsorbed to the matrix of a Superose 12 FPLC column during gel permeation chromatography (GPC) of milk protein hydrolysates. The adsorption phenomenon was most obvious when hydrolysates were prepared using enzyme mixtures which contained exopeptidases. The elution areas of peaks for tryptophan and tyrosine from a Superose 12 column was linear with concentration in the range 0 to 1 μmol. ml-1. Amino acid analysis confirmed that a strongly adsorbed peak in the elution profile, measured by absorbance at 280 nm, of an extensively hydrolysed rennet casein contained tryptophan. Individual hydrophobic peptides, used as molecular weight markers, also interacted with the column, eluting later than expected. Nitrate in a general water supply used for the production of a whey protein hydrolysate on a pilot-scale was responsible for the appearance of an additional peak in the elution profiles from a Superose 12 column, as measured by absorbance at 214 nm.