Zein/Gallic Acid Composite Nanoparticles to Improve the Oxidation Stability of Corn Oil Pickering Emulsion

In this paper, zein and gallic acid (GA) were used to prepare zein/gallic acid composite nanoparticles (ZGP) by antisolvent precipitation. Meanwhile, ZGP was used as stabilizer to prepare antioxidant Pickering emulsion. The results showed that ZGP exhibited good dispersivity in the nanometer scale and positive zeta potential. The bonding between Zein and GA was achieved mainly through hydrogen bonds, and X-ray diffraction analysis demonstrated that the resultant complex showed an amorphous structure. Thermodynamic analysis proved that the reaction between Zein and GA was spontaneous and exothermic, the surface hydrophobicitygradually decreased, and the thermal stability of ZGP increased with increasing GA addition. Furthermore, the Pickering emulsion stabilized by ZGP showed a shear thinning phenomenon typical of a non-Newtonian fluid, and the storage modulus (G’) was higher than the loss modulus (G”). During the storage period (50 ℃, 20 d), the amounts of primary and secondary lipid oxidation products both gradually decreased with an increase in GA concentration, indicating that the ZGP stabilized Pickering emulsion has antioxidant capacity and can inhibit lipid oxidation.