The effect of sodium chloride on the formation and stability of sodium caseinate emulsions

Studies have been made of changes in particle sizes, surface coverage and composition, and stability of emulsions formed with soya oil and sodium caseinate. Different concentrations of NaCl (0–1000 mM) were added before and after homogenization. Addition of NaCl before and after homogenization had no significant effect on average size of emulsion droplets in all emulsion systems studied. In emulsions made with 1 or 3% (w/w) caseinate, addition of NaCl up to 40 mM resulted in an increase in surface protein concentration (mg/m2) which appeared to be due largely to the enhanced adsorption of αs1-casein at the droplet surface, particularly in emulsions formed with 1% caseinate. Emulsion formed with 3% caseinate in the absence of NaCl showed extensive flocculation of emulsion droplets that resulted in very low creaming stability. Addition of NaCl up to 200 mM decreased the extent of flocculation and improved the creaming stability.