Page analysis of milk proteins altered by high thermal treatment

Abstract

Changes that occur in milk proteins during heat treatment were studied. Milk was heat treated at 87 degrees C for 10 min. Samples of untreated milk, demineralised whey powder and heat treated milk were analysed by discontinuous PAGE and by densitometric analysis of destained gels. PAGE experiments showed that heat treatment induces changes on milk proteins. During heating at 87 degrees C for 10 min all amount of beta-lactoglobulin present in milk interacted with casein, while small amount of alpha-lactalbumin did not interact with casein. It could be hypothesised that heating of milk at 87 degrees C for 10 min influences complete denaturation of beta-lactoglobulin and formation of complex with casein, while alpha-lactalburnin denatures and interacts with beta-lactoglobulin when beta-lactoglobulin has already linked with casein micelles.