Freeze–thaw stability of lecithin and modified starch-based nanoemulsions

The impact of freeze–thaw cycles on the physical stability of oil-in-water emulsions containing lecithin – coated and modified starch – coated droplets has been studied by combined dynamic light scattering (DLS) and differential scanning calorimetry (DSC) measurements. Emulsions prepared by high-pressure homogenization were within 200 nm size ranges. Lecithin-based emulsion systems were unstable to freeze–thaw cycles, which was attributed to extensive droplet aggregation induced by the ice formation during emulsion freezing process. Instead, modified starch systems were highly stable due to the formation of a thick layer of emulsifier which prevented the coalescence of nanoemulsions. The addition of ice nucleating protein lowered the freeze–thaw stability of lecithin-based emulsions, but had negligible effect on modified starch-based emulsions. In contrast, the addition of poly(ethylene glycol) improved the stability of lecithin-based emulsions but destabilized the modified starch-based emulsion systems.