title: Interfacial composition and stability of emulsions made with mixtures of commercial sodium caseinate and whey protein concentrate.
abstract: The interfacial composition and the stability of oil-in-water emulsion droplets (30% soya oil, pH 7.0) made with mixtures of sodium caseinate and whey protein concentrate (WPC) (1:1 by protein weight) at various total protein concentrations were examined. The average volume-surface diameter (d32) and the total surface protein concentration of emulsion droplets were similar to those of emulsions made with both sodium caseinate alone and WPC alone. Whey proteins were adsorbed in preference to caseins at low protein concentrations (<3%), whereas caseins were adsorbed in preference to whey proteins at high protein concentrations. The creaming stability of the emulsions decreased markedly as the total protein concentration of the system was increased above 2% (sodium caseinate >1%). This was attributed to depletion flocculation caused by the sodium caseinate in these emulsions. Whey proteins did not retard this instability in the emulsions made with mixtures of sodium caseinate and WPC.
authors.affiliation: Riddet Centre, Massey University, Private Bag 11 222, Palmerston North, New Zealand; Fonterra Research Centre, Fonterra Co-operative Group Limited, Dairy Farm Road, Private Bag 11 029, Palmerston North, New Zealand. Electronic address: aiqian.ye@fonterra.com.
authors.forename: Aiqian
authors.initials: A
authors.lastname: Ye
keywords: Adsorption; Creaming stability; Oil-in-water emulsion; Sodium caseinate; Whey protein concentrate