基于玉米醇溶蛋白/没食子酸复合纳米颗粒提升玉米油Pickering乳液的氧化稳定性

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

以玉米醇溶蛋白(Zein)和没食子酸(gallic acid,GA)为原料,通过反溶剂沉淀法制备玉米醇溶蛋白/没食子酸复合纳米颗粒(zein/gallic acid composite nanoparticles,ZGP),并利用ZGP作为稳定剂制备具有抗氧化能力的Pickering乳液。结果表明,ZGP呈现纳米级别且分散性良好,Zeta电位呈正值。Zein和GA主要通过氢键结合,通过X射线衍射结果证明了二者结合后呈现非定形结构。热力学分析证明Zein和GA之间的反应为自发放热反应,随着GA添加量增加,ZGP的表面疏水性逐渐下降,ZGP的热稳定性增强。此外,由ZGP稳定的Pickering乳液呈现剪切稀化现象,属于非牛顿流体,且储能模量(G’)高于损耗模量(G”)。在贮藏期间(50℃、20 d)初级氧化产物和次级氧化产物均随着GA添加量的增多而逐渐减少,说明由ZGP稳定的Pickering乳液具有一定的抗氧化能力,能在一定程度上抑制油脂氧化。

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.