New method for separation and determination of denatured caseins by hydrophobic interaction chromatography

A new method for the separation of denatured alpha-, beta- and kappa- casei ns by hydrophobic interaction chromatography (HTC) is proposed. The method is based on an easy solubilization of commercial and real samples by 4.0 M guanidine thiocyanate (GdmSCN) and elution on a TSK-Gel(R) Phenyl-5PW colum n (TosoHaas) in the presence of 8.0 M urea in the mobile phase. The procedu re, applied to commercial caseins and to real, raw samples (whole milk powd er and fat-free yoghurt) is not expensive, it requires common high performa nce liquid chromatography (HPLC) instrumentation and allows the separation of caseins also in the presence of whey proteins. Quantitative results on t he analysis of alpha-, beta- and kappa -caseins in real samples are also re ported. (C) 2001 Elsevier Science B.V. All rights reserved.