Controlling heat induced aggregation of whey proteins by casein inclusion in concentrated protein dispersions

Abstract

Formation of soluble, heat stable whey protein (WP) particles may be achieved via caseins and their chaperone like activity. The aim of this study was to establish effects of caseins on the properties of heat induced WP aggregates. Concentrated dairy protein mixtures (10% total-solids) were prepared with various casein:WP ratios (5:95-30:70) at adjusted pH (5.7-7.5) and heated to 80-120°C, under a constant shear (500s-1). Increasing casein fraction at higher pH reduced the average size of WP aggregates and the surface hydrophobicity with simultaneous reduction in apparent viscosity at pH 6.7. WP denaturation was minimal when 30% casein was included in the dispersions. Inhibition of WP denaturation at elevated pH with inclusion of caseins may be attributed to a chaperon like activity of the casein. Thus, by increasing pH and the casein content in the system it was possible to form nano-size whey protein particles.