Casein degradation in Cheddar cheese monitored by capillary electrophoresis

This study has shown the potential of using capillary zone electrophoresis to follow casein degradation in cheese. Resolution of all caseins was achie ved in a single run using one type of capillary, in contrast to ion-exchang e FPLC chromatography which requires casein fractionation on both cation- a nd anion-exchange columns. Additionally, large quantities of expensive solv ents and time-consuming buffer preparations are eliminated with the nanosca le injection volumes required. Casein quantification is more accurate than that which can be achieved by d ensitometric scanning of electrophoresis gels, where variations in the inte nsity of band staining and the dependence on being able to accurately integ rate the peak areas for each of the components must be considered. Differen ces in the relative casein concentration levels determined between the stan dard and reduced pH Cheddar cheeses, allow quantification of proteolysis to be made which would not have been possible from the equivalent SDS-PAGE ge ls. This study has shown capillary zone electrophoresis to be an inexpensive an d rapid technique, ideally suited for the quantification and comparison of proteolysis in cheese manufactured under a range of different processing co nditions.