Effect of processing and storage parameters on the oxidative deterioration of oil-in-water emulsions

The effect of storage temperature, pH, and homogenization pressure on the oxidative deterioration of Tween 20 and sodium caseinate sunflower oil-in-water emulsions was studied by monitoring conjugated dienes (M), lipid hydroperoxides (LH), and thiobarbituric, acid reactive substances (TBARs). CD increased linearly with storage time, and the rate constant was temperature dependent according to the Arrhenius equation with an activation energy equal to 37.5 kJ mol(-1). The increase in LH and TBARs with temperature (5-60 degrees C) was in good agreement with CD variation. Tween-stabilized emulsions oxidized faster as pH increased from 3 to 7, whereas a different behavior was observed in emulsions stabilized with sodium caseinate or a mixture of both emulsifiers. A change of homogenization pressure (30-900 bars), reflecting variation of emulsion average droplet size, had no effect on the oxidative stability of the emulsions.