OIL-IN-WATER EMULSIONS STABILIZED BY SODIUM CASEINATE OR WHEY-PROTEINISOLATE AS INFLUENCED BY GLYCEROL MONOSTEARATE

Competitive adsorption between glycerol monostearate (GMS) and whey pr otein isolate (WPI) or sodium caseinate was studied in oil-in-water em ulsions (20 wt % soya oil, deionized water, pH 7). Addition of GMS res ulted in partial displacement of WPI or sodium caseinate from the emul sion interface. SDS-PAGE showed that GMS altered the adsorbed layer co mposition in sodium caseinate stabilized emulsions containing less tha n or equal to 1.0 wt % protein. Predominance of beta-casein at the int erface in the absence of surfactant was reduced in the presence of GMS . The distribution of alpha-lactalbumin and beta-lactoglobulin between the aqueous bulk phase and the fat surface in emulsions stabilized wi th WPI was independent of the concentration of added protein or surfac tant.