Citral Stability in Oil-in-Water Emulsions with Solid or Liquid Octadecane

Citral stability in oil-in-water emulsions at pH 3.0 with solid or liquid octadecane was determined. Citral degradation was faster in anionic sodium dodecyl sulfate (SDS)-stabilized emulsions than non-ionic polyoxyethylene (23) lauryl ether (Brij)-stabilized emulsions. Crystallization of octadecane in both Brij- and SDS-stabilized emulsion droplets resulted in faster degradation of citral. Crystallization of octadecane in emulsion droplets increased citral partitioning into the aqueous phase, with 41-53% of the total citral in the aqueous phase when octadecane was solid compared to 18-25% when octadecane was liquid. This research suggests that factors that increase partitioning of citral out of the droplets of oil-in-water emulsions increase citral degradation rates. These results suggest that the stability of citral could be increased in oil-in-water emulsions by technologies that decrease its partitioning and exposure to acidic aqueous phases.