Formation and properties of the whey protein/κ-casein complexes in heated skim milk — A review

The formation of complexes between whey proteins and κ-casein during heat treatment of milk dramatically affects the protein organisation in both the colloidal casein and the serum phases of milk and consequently, its technological applications. This paper reviews the composition and building interactions of these complexes and their localisation between the casein micelle and lactoserum. The currently proposed mechanisms that lead to their formation are also presented. The physico-chemical properties of these complexes, in terms of structure, size and surface properties are described and the technological means by which these properties could be controlled are discussed. Finally, the current hypotheses that explain the functional properties of these complexes in the heat-induced changes of dairy applications are reviewed, with emphasis on acid gelation of milk.