Isolation and characterisation of kappa-casein/whey protein particles from heated milk protein concentrate and role of kappa-casein in whey protein aggregation

摘要

Milk protein concentrate (79% protein) reconstituted at 13.5% (w/v) protein was heated (90 degrees C, 25 min, pH 7.2) with or without added calcium chloride. After fractionation of the casein and whey protein aggregates by fast protein liquid chromatography, the heat stability (90 degrees C, up to 1 h) of the fractions (0.25%, w/v, protein) was assessed. The heat-induced aggregates were composed of whey protein and casein, in whey protein: casein ratios ranging from 1:0.5 to 1:9. The heat stability was positively correlated with the casein concentration in the samples. The samples containing the highest proportion of caseins were the most heat-stable, and close to 100% (w/w) of the aggregates were recovered post-heat treatment in the supernatant of such samples (centrifugation for 30 min at 10,000 x g). kappa-Casein appeared to act as a chaperone controlling the aggregation of whey proteins, and this effect was stronger in the presence of alpha(S)- and beta-casein. (C) 2017 Elsevier Ltd. All rights reserved.