功能性蛋白质微胶的制备、结构表征及输送与界面性质研究

Protein microgels (PMG) with meso-scale structure, surface active and lipophilic binding capability have provided a possibility of utilization as novel food functional ingredients for the delivery of bioactives and interfacial stabilizier. This study aims at establishing an efficient commercial technology of PMG preparation with protein modification and pH/temperature control, by which the PMG can be fabricated through manipulation of the self-limited aggregation and self-assembly of protein during heating and phase inversion. The delivery and interfacial properties of functional PMG are studied. The research contents including: (1) Formation capability, mechanism and structural characterization of PMG prepared by heat treatment at control pH, antisolvation and bulk gel dispersion methods.The formation mechanism and structural properties of PMG are monitored and characterized by SAXS, DLS，Cro-SEM, TEM, CD, ATR-FTIR and SEC-LALS. (2) Preparation of nutritive PMG and its loading and delivery capability of hydrophobic nutrients and bioactives. The nutritive PMG are fabricated by protein-polysaccharides block co-polymer through co-assembly technology. The release of loading nutrients and the capacity of Caco-2 cell adhesion and absorption are studied in vitro and in vivo, the bioavailability and bioconversion of bioactives loaded in PMG are also studied with animals experiments. (3) Preparation of surface-active and core-shell PMG and their capability of acting as efficient emusifier and interface stabilizer. The surface-active PMG are fabricated by amphiphilic modification, by which the protein are grafted with polysaccharides through Maillard reaction, followed by limited protein hydrolysis. The core-shell PMG are prepared by Layer-by-Layer (LbL) electric deposition technology with polysaccharides, followed by enzymatic cross-linking. The Pickering emulsions and foams stabilized by functional PMG are prepared and the interfacial properties of PMG are also studied. This study will provide food industry a possibility of extending the utilization of protein microgels.

蛋白质微胶具有优异的尺寸效应、表面效应和疏水配体结合能力，可望成为新一代的功能性食品配料。本项目基于具有工业应用前景的蛋白质微胶制备技术，试图通过蛋白质修饰及环境因素的调节策略，精确控制蛋白质的聚集和自组装行为，构建不同功能特性的蛋白微胶，从营养输送及界面稳定两个角度研究蛋白质微胶的功能性质，为其应用于食品体系提供理论基础与技术支撑。研究内容：(1) 蛋白质微胶的制备、结构表征及形成机制研究。采用热处理、反溶剂及宏凝胶分散技术制备蛋白微胶，表征蛋白质微胶结构及蛋白质聚集体形成动力学；（2）营养微胶的构建及输送特性研究。通过嵌段共聚物共组装技术实现植物蛋白对疏水性生物活性物质的荷载，在细胞与动物水平上研究其生物可及性及生物可利用度；(3) 表面活性蛋白微胶的构建及Pickering乳液的研究。通过蛋白质与多糖相互作用制备表面活性微胶及核/壳微胶，研究蛋白质微胶作为乳化剂和界面稳定剂的可行性。

蛋白质微胶具有优异的尺寸效应、表面效应和疏水配体结合能力，可望成为新一代的功能性食品配料。本项目基于具有工业应用前景的蛋白质微胶制备技术，试图通过蛋白质修饰及环境因素的调节策略，精确控制蛋白质的聚集和自组装行为，构建不同功能特性的蛋白微胶，从营养输送及界面稳定两个角度研究蛋白质微胶的功能性质，为其应用于食品体系提供理论基础与技术支撑。研究内容：①蛋白质微胶的制备、结构表征及形成机制研究。采用宏凝胶分散技术制备蛋白微胶，其理化及界面性质进行了系统的表征；该微胶颗粒既可作为Pickering类型乳液稳定剂，也可以作为活性物质输送载体在食品体系中应用。②营养微胶的构建及输送特性研究。利用蛋白质结构的双亲性，通过超声诱导、NAB技术等，开发了大豆蛋白/甜菊甙、大豆亲脂性蛋白、胰蛋白酶抑制剂等多种疏水活性物质载体，并对其结构和输送特性进行了系统研究。③表面活性蛋白微胶的构建及Pickering乳液的研究。研究了多种植物蛋白与小分子物质如表面活性剂（硬脂酸盐）、多酚（单宁酸）、皂甙（甜菊甙和皂树皂甙）和植物甾醇（谷甾醇）等复合物在油/水及气/水界面的行为，并以其作为界面稳定剂获得了多种具有良好储藏及抗氧化稳定性的乳液和泡沫体系。以此为基础，提出了简单、经济的制备无氢化油结构化乳液及油粉的方法，构建了具有等级结构的乳液，考察了风味物质在此多种体系下的控制释放特性以及食品色素在等级乳液及油胶不同位置对其色彩呈现的影响。④以喷射蒸煮制备了高异黄酮含量的大豆蛋白，对其进行乳酸菌接种，制备了具有良好异黄酮和蛋白质生物利用度的发酵豆奶。发现了富含异黄酮苷元大豆蛋白可有效防止骨质疏松症。