多酚调控玉米醇溶蛋白胶粒界面组装的微观历程及机制

Food soluble components effect the surface properties of food colloidal particles, and then influence the interaction between them, finally intervene their interfacial assembly behavior. This micro-process has not yet been fully concerned about, but closely related to food quality and nutritional properties. Based on the previous research that polyphenols can significantly improve the interfacial stability of zein colloidal particles, this project intends to lucubrate the three stages and reveal the progressive links between them, in order to systematically elucidate the micro-process and mechanisms of polyphenols regulating the interfacial assembly of zein colloidal particles. In this project, tannic acid, EGCG and gallic acid with different amounts of ortho-triphenols group are taken as representatives. Firstly, the effect of polyphenols structure and key factors (pH, modification method, polyphenol concentration, etc.) on the microstructure and surface properties (including particle size, zeta potential, surface functional groups, and surface wettability, etc.) of colloidal particles will be investigated. Subsequently, the interaction between the colloidal particles in water phase and on the interface will be explored via total internal reflection microscopy, AFM, and QCM-D methods. Finally, the interfacial adsorption and assembly, mechanical behavior and interfacial microstructures will be investigated. The implementation of the project will enrich the cognition of colloidal interfacial assembly and offer a reference for understanding the complex interactions of multi-component and multi-phase food system, also provide a theoretical basis for quality control of interface-dominated food systems.

食品可溶性组分影响食品胶粒表面特性，进而影响胶粒间相互作用，再而影响其界面组装行为，是尚未被充分关注，却与食品品质及营养特性密切相关的微观历程。项目在多酚可极显著提高zein胶粒界面稳定性这一前期发现的基础上，拟利用该体系对上述微观历程的三个阶段逐一深入研究，并揭示三阶段之间的递进联系，系统阐明多酚调控zein胶粒界面组装的微观历程及机制。研究以邻三元酚结构数量不同的单宁酸、EGCG、没食子酸为代表，首先研究多酚结构和关键因素（pH、修饰方式、多酚浓度等）对zein胶粒微观结构及粒径、电位、表面官能团、润湿性等表面特性的调控，进而利用全内反射显微镜、AFM、QCM-D等方法探究水相及界面上胶粒间的相互作用，最后对其界面吸附及组装、界面力学行为和界面微结构进行表征。项目的实施将丰富对胶体界面组装的认识，为理解食品多组分多相复杂相互作用提供参考，为界面主导型食品体系的品质调控提供理论依据。

食品多组分间的交互作用对食品质构、品质与营养特性影响显著，特别是对乳液、泡沫、悬浮液等界面主导型食品体系的形成和稳定至关重要。研究发现多酚可显著提高zein胶粒界面稳定性，但其内在机制却不明晰。本项目以邻三元酚结构数量不同的单宁酸、EGCG、没食子酸为研究对象，首先系统探索了多酚浓度、比例、修饰方式等因素对zein胶粒表面特性的影响规律。结果发现，多酚的引入可改变zein胶粒的表面荷电性质，且可降低zein胶粒的表面疏水性，采用两步法（先混合后修饰）获得的复合胶粒具有更强表面亲水性；随后结合荧光光谱等光谱学和QCM-D等手段探究不同结构多酚与zein之间相互作用，发现zein与TA，EGCG以氢键作用结合，而与GA以疏水相互作用结合，且TA可增强纳米颗粒间的相互作用；最后结合悬滴法和LB膜法考察复合纳米粒子在界面的吸附行为，结果表明，其表面性质的改变不仅影响了颗粒间的相互作用，也抑制了zein胶粒由于较强的疏水性而导致的聚集行为；此外，多酚的引入不仅减缓了胶粒向油水界面的吸附速度，也降低了复合胶粒在油/水界面上的扩散速率，复合胶粒的扩散速率均低于zein胶粒，从而促使颗粒在界面上的吸附及重排时间延长，形成具有粘弹性的界面膜。该项目可拓宽人们对胶体界面组装行为的认识，为理解食品多组分多相复杂相互作用提供参考，亦为界面主导型食品体系的品质调控提供理论依据与数据支撑。