FORMATION AND COALESCENCE STABILITY OF EMULSIONS STABILIZED BY DIFFERENT MILK-PROTEINS

The volume fraction of oil emulsified, surface area, droplet diameter, and coalescence rates of emulsions stabilized by different milk proteins were studied at protein concentrations of 0.25; 0.5, 1.0, and 2.0% (w/w); pH 4, 5, and 7; and ionic strengths 0.1 and 0.2. The emulsion activity index (EAI) and coalescence stability generally increased with increasing protein solubility and hydrophobicity. The volume fraction of oil emulsified decreased with increasing ionic strength. Coalescence stability correlated with droplet diameter for emulsions stabilized by alpha-lactalbumin, beta-lactoglobulin, and sodium caseinate (r2 = 0.96). With the exception of beta-lactoglobulin-stabilized emulsions, coalescence stability was largely unaffected by pH.