Fabrication and Characterization of Antioxidant Pickering Emulsions Stabilized by Zein/Chitosan Complex Particles (ZCPs)

Lipid peroxidation in oil-in-water (o/w) emulsions leads to rancidity and carcinogen formation. This work attempted to protect lipid droplets of emulsions from peroxidation via manipulation of the emulsions' interface framework using dual-function zein/CH complex particles (ZCPs). ZCP with intermediate wettability was fabricated via a simple antisolvent approach. Pickering emulsions were produced via a simple and inexpensive shear-induced emulsification technique. ZCP was irreversibly anchored at the oil-water interface to form particle-based network architecture therein, producing ultrastable o/w Pickering emulsions (ZCPEs). ZCPE was not labile to lipid oxidation, evidenced by low lipid hydroperoxides and malondialdehyde levels in the emulsions after thermally accelerated storage. The targeted accumulation of curcumin, a model antioxidant, at the interface was achieved using the ZCP as interfacial vehicle, forming antioxidant shells around dispersed droplets. The oxidative stability of ZCPEs was further improved. Interestingly, no detectable hexanal peak appeared in headspace gas chromatography of the Pickering emulsions. The novel interfacial architecture via the combination of steric hindrance from ZCP-based membrane and interfacial cargo of curcumin endowed the emulsions with favorable oxidative stability. This study opens a promising pathway for producing antioxidant emulsions via the combination of Pickering stabilization mechanism and interfacial delivery of antioxidant.