COMPETITIVE ADSORPTION AND PROTEIN SURFACTANT INTERACTIONS IN OIL-IN-WATER EMULSIONS

Competitive adsorption in oil-in-water emulsions has been investigated for binary protein/protein and protein/surfactant systems. Analysis of aqueous phase composition in emulsions (10 wt % n-tetradecane, pH 7) indicates fast reversible adsorption for alpha-s1 -casein/beta-casein, but slow irreversible adsorption for beta-casein/alpha-lactalbumin, beta-casein/beta-lactoglobulin and alpha-lactalbumin/beta-lactoglobulin. Surface viscosity data at the planar oil-water interface give further information on milk protein competitive adsorption. Interfacial tensions and viscosities are reported for a mixture of a non-ionic surfactant, octaoxyethylene dodecyl ether (C12E8), and sodium caseinate; and stability data are presented for emulsions made with C12E8 + caseinate. Differences between C12E8 and the anionic surfactant, sodium dodecyl sulphate (SDS), are noted.