蛋白限制性结构修饰调控乳液消化及功能输送特性的机理研究

Protein structure, both at interface and bulk phase, is a key factor affecting the stability, digestion and functional delivery of protein emulsion. In this study, a new type of food protein-based emulsion system, including multi-layer emulsion and emulsion gel, was prepared by means of controlled oxidative modification in combination with limited enzymatic treatment, designed from the view of hierarchical structure with the purposes of controlling lipid digestion and lipophilic nutrients delivery. The research contents mainly include: (1) establishment of controlled oxidative and limited enzymatic modification system, fabricating protein units with different structures, morphology and surface properties, (2) exploring the relationship between protein structure and emulsion formation and stabilization. Systematic characterization of protein adsorption/assembly at interface, interaction between protein at interface and non-interface, as well as those interfacial behavior in relation to emulsion microstructure, (3) Protein emulsion structure in relation to lipid digestion and functional delivery. Physical-chemical properties of protein emulsion underwent in vitro gastric-intestinal tract, digestion kinetics of lipid and fatty acids release profile were particularly emphasized. Lipophilic nutrients delivery behavior of protein emulsion in vitro was further carried out. Inner relationship between protein structure and emulsion digestion and functional delivery properties were investigated. This project will reveal the intrinsic relationship between protein structure and emulsion digestion and functional delivery, further providing new ideas and theoretical guidance for the development of new functional foods and food ingredients.

蛋白质结构是影响蛋白乳液稳定、消化及功能性输送的关键因素。本研究以动/植蛋白质为结构单元，利用层次结构设计原理，通过限制性氧化及生物酶处理等手段适度修饰蛋白结构，构建新型食物蛋白基乳液体系，包括多层乳液及乳液凝胶结构，分别达到调控脂肪消化及亲脂性营养素输送的目的。研究内容包括：（1）建立限制性氧化及生物酶修饰体系，制备不同结构、形貌及表面特性的蛋白结构单元；（2）蛋白结构调控乳液形成及稳定性的关系探究。系统表征蛋白在界面的吸附/组装、界面/体相蛋白的交互作用及与乳液微结构的关系；（3）蛋白乳液的脂肪消化及功能输送特性研究。重点表征消化过程中乳液性质的变化及脂肪消化动力学，研究蛋白结构对脂质消化及活性输送的调控机制。本项目将揭示蛋白结构与乳液脂肪消化及功能输送特性的内在关联，为开发新型功能食品及食品配料提供新思路和理论指导。

食物蛋白乳液是食品工业中最重要的体系之一，也是脂质在加工食品中存在的主要形式。近年来研究显示通过调控蛋白乳液的消化进程以减少脂质吸收是控制食物热量摄入的有效途径。相较于天然蛋白，由蛋白纳米颗粒稳定的皮克林乳液（Pickering emulsion）在乳液的稳定性以及延缓脂质消化方面具有显著优势，在低热量乳液食品研发上显示出巨大的应用前景。因此，如何以更高效、可持续的方式制备高乳化能力的食物蛋白胶体颗粒以制备皮克林乳液并实现乳脂消化的有效调控已成为现代健康乳液食品领域的研究热点。基于此，本论文以大宗植物蛋白大豆分离蛋白（SPI）为原料，采用可控生物酶解技术成功制备出结构与功能特性可控的大豆蛋白纳米颗粒（Soy protein nanoparticles，SPNP），系统表征和探究了SPNP的结构特性与形成机制；进一步以SPNP为界面稳定剂制备出皮克林乳液，研究了SPNP荷载界面对乳脂消化行为的调控作用及机制。