Effects of sodium caseinate concentration and storage conditions on the oxidative stability of oil-in-water emulsions

The oxidative stability of various oils (sunflower, camelina and fish) and 20% oil-in-water (O/W) emulsions, were examined. The mean particle size decreased from 1179 to 325 nm as sodium caseinate (emulsifier) concentration was increased from 0.25% to 3% in O/W emulsions (P < 0.05). Increasing the microfluidisation pressure from 21 to 138 MPa, resulted in a particle size decrease from 289 to 194 nm (P < 0.05). Emulsified oils had lower detectable lipid hydroperoxide and p-Anisidine values than their corresponding bulk oils (P < 0.05). The lipid hydroperoxide and p-Anisidine values of emulsions generally decreased as sodium caseinate concentration increased, and similarly decreased as microfluidisation pressure increased (P < 0.05). Increasing storage temperature of the emulsions from 5 to 60 °C, resulted in lower detectable lipid oxidation products during storage (P < 0.05).