THERMAL-STABILITY AND FUNCTIONALITY OF WHEY PROTEINS

Functional properties of whey proteins are often impaired by inevitable heat treatments during processing of whey protein products and preservation of food products. The extent of deterioration depends on the relation between the rate of protein denaturation and the heat load applied. In a new kinetic approach, whey protein denaturation is split into two successive processes: 1) unfolding, determined by differential scanning calorimetry; and 2) aggregation, derived from high performance gel permeation chromatography. A short review is presented of industrial recovery processes of whey protein products and their related functional properties. The effect of heat treatments between 70 and 90-degrees-C is analyzed in terms of the kinetics of whey protein unfolding and aggregation. The results reveal that thermal denaturation of whey proteins during industrial heating processes is predictable. An important determinant for functional properties is the salt composition of whey protein products during heat treatments at temperatures above 75-degrees-C.