Effect of Oil-Droplet Diameter on Lipid Oxidation in O/W Emulsions

The effect of oil-droplet diameter on lipid oxidation in O/W emulsions is unclear, and conflicting results have been reported. These conflictions may be due to different experimental conditions being used, such as the type of oil, the type of emulsifier, temperature, and the range of oil-droplet diameters tested. The method used to evaluate the oxidation could also have varied among studies. In O/W emulsions, oxygen dissolved in the aqueous phase is transferred to the oil phase through the oil-water interface and is consumed in the oil phase by oxidation. Therefore, the effect of the oil-droplet diameter on the lipid oxidation rate was evaluated by simultaneously solving the mass balance equations of oxygen and oil in the oil phase. The simulation showed that the oil-droplet diameter does not affect the lipid oxidation rate in O/W emulsions with oil-droplet diameters on the order of micrometers or less because the oxidation reaction itself is rate-limiting.