Assessment of casein content model systems during heat treatment

Abstract

Heat treatment affects the sensory, biophysical and nutritional properties of milk. To maintain and improve milk quality, an optimization of the heat treatment must be reached to ensure the microbiological safety of the product, while altering as little as possible its sensory and nutritional value. One of the major events occurring upon heating is protein denaturation. The rate of protein denaturation is governed by the immediate chemical environment of the reactants defined by the chemical composition of the system. The aim of the present work was to compare the kinetics of casein denaturation under different conditions, in order to define suitable markers to sensitively assess the degree of reaction in early stages accounting for the time/temperature effects. The results showed a clear dependence of protein denaturation on pH and calcium content, but temperature-time combination did not have a major impact on the extent of protein heat-induced changes.