Characterisation of modified whey protein in milk ingredients by liquid chromatography coupled to electrospray ionisation mass spectrometry

Whey proteins are an important ingredient in the food industry. We have inv estigated the protein composition of commercial whey samples by liquid chro matography coupled to electrospray ionisation mass spectrometry on a time-o f-flight instrument. We found that industrial whey protein contains a multi tude of different modifications, ranging from almost native proteins throug h different degrees of glycosylation and oxidation up to almost completely oxidised forms. The information obtained allows characterisation of the inf luence of industrial processing on protein modifications and classification of whey protein-based ingredients or milk powders from different suppliers . (C) 2001 Elsevier Science B.V. All rights reserved.