Chapter 9 - The Whey Proteins in Milk: Thermal Denaturation, Physical Interactions, and Effects on the Functional Properties of Milk

Abstract

This chapter reviews the literature on the denaturation of the whey proteins in milk, examines their interaction with other milk protein components, and provides some examples on the relationships between denaturation/interaction reactions of the whey proteins and the functional behavior of the milk in selected applications. Early studies on whey protein denaturation in milk were aimed at developing methods to assess denaturation levels, and determining the relationships between the denaturation of the whey proteins and the functional behavior of milk products in bakery and other applications. Subsequent studies were directed toward modeling the whey protein denaturation processes through kinetic and thermodynamic evaluations, and determining the role of various milk components on these denaturation processes. Although the denaturation of whey proteins is critical in modifying the functional behavior of dairy products, it has become increasingly apparent that a measure of the denaturation level alone is not in itself a good predictor of functional performance. Therefore further studies have investigated the interactions of the denatured whey proteins with other milk protein components, in particular the interactions between the denatured whey proteins and the casein micelles (including identification of the specific disulfide bonds involved in complex formation between the denatured β-lactoglobulin and κ-casein). A limited number of recent studies have indicated that manipulation of the interactions of the denatured whey proteins with the other milk protein components may provide a significant tool for modifying or controlling the functional performance of milk protein products in some applications.