Emulsions of 0.1 wt % corn oil-in-water containing oil droplets coated by β-lactoglobulin (0.009 wt % β-Lg, 5 mM phosphate buffer, pH 7.0) were prepared in the absence and presence of sodium alginate (0 or 0.004 wt %). The pH (3−7) and ionic strength (0−250 mM NaCl) of these emulsions were adjusted, and the particle charge, particle size, and creaming stability were measured. Alginate adsorbed to the β-Lg-coated droplets from pH 3 to 6, which was attributed to electrostatic attraction between the anionic polymer and cationic patches on the droplet surfaces. Droplets coated by β-Lg−alginate had better stability to flocculation than those coated by β-Lg alone, especially around the isoelectric point of the adsorbed proteins and at low ionic strengths (<100 mM>NaCl). At pH 5, alginate molecules desorbed from the droplet surfaces at high salt concentrations due to weakening of the electrostatic attraction.
Available at: http://works.bepress.com/djulian_mcclements/113/