Aggregation kinetics of heated whey protein-stabilised emulsions: effect of low-molecular weight emulsifiers

The heat-induced aggregation of emulsions made with mixtures of whey protein and varied molar ratios of water-soluble or oil-soluble low molecular weight surfactants was followed using laser light scattering. At low molar ratio the water-soluble surfactants Tween-60 and phosphatidylcholine increased the aggregation rate, whereas at higher molar ratios the aggregation rate decreased. For oil-soluble surfactants (glycerol monostearate and Span-60) the aggregation rate showed an increase at high molar ratio. Differences in the rate of heat-induced aggregation are explained in terms of possible changes in the conformation of adsorbed whey protein, observed differences in the protein surface coverage, and the formation of protein-surfactant complexes.