黄原胶/溶菌酶颗粒构建pH稳定化Pickering乳液及其界面组装机理

Protein/polysaccharide particles become an important source of particle stabilizers in Pickering emulsion due to its outstanding advantages. pH stability is the basis of its application in nutrient enrichment, food manufacturing and other fields. However, litter is known about regulating colloidal particle pH sensitivity and emuslion pH stability. Our previous results showed that properties of xanthan gum/lysozyme particles could be changed through preparation condition regulation, which further affected their interfacial behavior. But the behavior of emulsion fabrication and stabilizing mechanism are not clear. Based on our previous research, the self-assembly behavior between xanthan gum and lysozyme will be further regulated in this project. pH stability of Pickering emulsions is regulated through changing properties of colloid particles and controlling emulsions synthesis parameters. Pickering emulsions with pH stability are fabricated finally. Interfacal assembly mechanisms of stabilizing Pickering emulsions by xanthan gum/lysozyme particles is explored from the point of interfacial adsorption kinetics, interfacial rheological properties, macrorheology, micro-rheology, in situ observation of morphology and deformation, and interaction bwteen interfacal compositions. The study not only provides research methods for regulating pH stability of protein/polysaccharide particles and Pickering emulsion, but also enriches interfacial assembly mechanism of protein/polysaccharide particles.

蛋白质/多糖胶体颗粒因其突出优势成为Pickering乳液稳定剂的重要来源，乳液pH稳定性是其在营养强化升级及食品加工等方面应用的基础，但目前人们对调控胶体颗粒pH敏感性与Pickering乳液pH稳定性的关系认识有限。前期研究表明，通过改变制备条件可调控黄原胶/溶菌酶胶体颗粒性质，并影响其界面特性，但其稳定乳液行为及界面组装机制还不清楚。本项目拟在前期研究基础上，进一步系统研究黄原胶、溶菌酶自组装行为，从颗粒性质及乳液制备参数两个方面调控Pickering乳液pH稳定性，建立pH稳定化Pickering乳液体系；并从吸附动力学、界面流变、宏观流变、微流变、原位外观和形变及界面组分互作，研究黄原胶/溶菌酶胶体颗粒的界面组装行为及其稳定乳液的机理。本研究对调控蛋白质/多糖胶体颗粒与Pickering乳液的pH稳定性提供方法的借鉴，丰富蛋白质/多糖胶体颗粒稳定乳液的界面组装机理。

Pickering乳液pH稳定性是其在营养强化升级及食品加工等方面应用的基础，为此，本项目紧密围绕调控Pickering乳液pH稳定性，建立pH稳定化Pickering乳液体系，研究黄原胶/溶菌酶胶体颗粒（XG/Ly NPs）的界面组装行为及其稳定乳液的机理，建立多糖干预、胶体颗粒浓度调控与Pickering乳液结构与特性的关系等关键问题，开展多方面的基础理论研究。阐明了XG/Ly胶体颗粒制备条件与颗粒特性的关系链，提出模拟制备条件（包括pH、热环境等），从光谱、流变学等角度原位探索多糖/蛋白质胶体颗粒制备的机理探索，结果表明在制备进程中，XG和Ly均失去了初始结构，形成了亚稳态复合体，热过程促进了分子进一步重组，使XG/Ly凝胶化。阐明XG/Ly NPs颗粒特性（颗粒大小、接触角等）、能量输入对其在油水界面上的扩散，渗透和结构变形及重排的影响，从界面吸附、颗粒稳定剂互作等角度建立制备pH稳定性Pickering乳液的预测机理，结果表明颗粒的界面吸附行为与颗粒大小有关，结构重排对界面稳定起着重要作用，颗粒稳定剂互作及能量的输入有助于多层界面薄膜的形成。通过XG及颗粒稳定剂浓度对Pickering乳液结构、稳定性、流变学特性的调控，探明多糖物理干预及颗粒浓度调控乳液多相态行为的影响，结果表明XG的干预及颗粒浓度的提高降低了乳液的液滴尺寸，促使连续相中形成致密的三维结构，因此减慢了液滴的迁移速度，进一步增强乳液的稳定性，提高颗粒浓度促使乳液体系从液体-半固体-固体进行转变，从而为拓宽乳液在食品的应用奠定良好理论基础。依托本项目，培养研究生3人，发表论文11篇，其中SCI论文10篇，申请发明专利5件（授权1件）。