Suppression of depletion flocculation in oil-in-water emulsions: a kinetic effect of β-lactoglobulin

This paper reports on creaming and flocculation in 10% (w/w) oil-in-water emulsions, stabilised by β-lactoglobulin (β-lg) and flocculated by dextran. Dextran and an additional amount of β-lg were added at various concentrations after emulsion formation. A substantial effect of the β-lg concentration was observed. At higher β-lg concentrations, a larger dextran concentration was required to induce network formation. This effect was explained by a retardation of the flocculation process at larger β-lg concentrations, shown by diffusing wave spectroscopy (DWS). This retardation was caused by the unexpectedly high apparent viscosity at low shear-rates of mixed solutions of β-lg and dextran.