Heat-induced aggregation of whey proteins in the presence of kappa-casein or sodium caseinate

Guyomarc'h, Fanny; Nono, Merveille; Nicolaï, Taco; Durand, Dominique

Heat-induced aggregation of whey proteins in the presence of kappa-casein or sodium caseinate

2009

Guyomarc'h, Fanny | Nono, Merveille | Nicolaï, Taco | Durand, Dominique

Aggregates were formed by heating mixtures of whey protein isolate (WPI) and pure κ-casein or sodium caseinate at pH 7 and 0.1 M NaCl. The aggregates were characterized by static and dynamic light scattering and size exclusion chromatography. After extensive heat-treatment at 80 °C for 24 h, almost all whey proteins and κ-casein formed mixed aggregates, but a large proportion of the sodium caseinate did not aggregate. At a given WPI concentration the size of the aggregates decreased with increasing κ-casein or sodium caseinate concentration, but the overall self-similar structure of the aggregates was the same. The presence of κ-casein or caseinate therefore inhibited growth of the heat-induced whey protein aggregates. The results were discussed relative to the reported chaperone-like activity of casein molecules towards heat aggregation of globular proteins. Keywords: Whey proteins; κ-Casein; Caseinate; Heat aggregation; Aggregate size

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