CALCIUM-INDUCED DESTABILIZATION OF OIL-IN-WATER EMULSIONS STABILIZED BY CASEINATE OR BY BETA-LACTOGLOBULIN

The stability to aggregation of 20% soya oil-in-water emulsions stabilized by 0.3 to 2% sodium caseinate or beta-lactoglobulin in the presence of calcium chloride solutions was studied using light scattering and electron microscopy. Stability increased with the amount of protein in the emulsion, and decreased with the concentration of added calcium. Growth of particle size with concentration of Ca2+ was more in emulsions containing lower concentrations of protein. Sodium chloride at 50 and 100 mM stabilized both systems to the presence of calcium ions. Microstructure and light scattering showed caseinate emulsions formed clusters even at low concentrations of Ca2+ while beta-lactoglobulin emulsions formed extensive strands.