Quantification of heat-induced casein–whey protein interactions in milk and its relation to gelation kinetics

Abstract

This paper describes a quantitative study on the distribution of denatured whey proteins over whey protein aggregates and whey proteins associated with the casein micelles in heated milk. This was done by combination of enzymatic fractionation and capillary electrophoresis. More severe heat treatment at the natural pH of milk caused more denaturation, but the ratio of denatured whey proteins associated with the casein micelle and present in aggregates remained constant. The distribution is related to changed acid-induced gelation properties and textural properties of milk-derived products. We clearly demonstrated that the observed shift in gelation pH of heated milk is linearly correlated with the distribution of denatured whey proteins. Quantitative description will allow better control and tuning of the final gel properties of milk-derived products.