超声波构建大豆分离蛋白-果胶复合传递系统的机理及效用研究

The delivery system could improve the bioavailability of functional food components as well as attach new functional properties to them. Recently, an important trend for the design of delivery systems is to prepare binary complexes/conjugates via protein-polysaccharide interactions. However, the traditional preparation methods are cumbersome and time-consuming, generally resulting in unsatisfying products. The applicant's preliminary study revealed that ultrasound could effectively improve the production efficiency of the soy protein isolate (SPI)-pectin conjugate and strengthen its functional properties. To conduct an in-depth study on the relevant mechanism, this project will firstly utilize the combination of ultrasound and enzymes to modify SPI and pectin. With the aid of MS, NMR and other means, the effect of the raw materials’ structures on the functionality of the electrostatic complexes/covalent conjugates will be illuminated. Then, we will apply ultrasound in the preparation of the electrostatic complexes/covalent conjugates; two types of binding models will be built by molecular simulation docking technology. Mechanisms of ultrasound free radical effects and mechanical effects will be clarified using high-speed photography and ESR technology. Finally, the dynamic high pressure microfluidization will be used to prepare nanoemulsions. The delivery properties of the complexes and conjugates will be studied using β-carotene as a core material. The relationship between the formation mechanism of different delivery systems and the functional properties of nanoemulsions will be elucidated. Results of this project will lay a theoretical foundation for the application of ultrasound in the preparation of protein-polysaccharide compound delivery systems. Also, it is of great importance for the high-value utilization of soybean and pectin resources, as well as technology innovation in the food industry.

传递系统可提高食品功能组分的生物利用率、并赋予其新的功能特性。利用蛋白-多糖相互作用构建二元复合物是近年来设计食源性功效因子传递系统的重要趋势。但传统制备方法繁琐耗时，产品功能不理想。申请人前期研究发现，超声波可有效提高大豆分离蛋白(SPI)-果胶复合物制备效率、强化其功能特性。为深入探索其机理，本项目首先利用超声波-酶联用技术定向改性SPI和果胶，借助MS、NMR等手段探索原料结构对静电/共价复合物功能的影响；然后将超声用于两类复合物构建中，利用分子模拟对接技术构造结合模型，借助高速摄影、ESR等技术阐明自由基效应和机械效应的作用机理；最后通过高压微射流技术构建纳米乳液，研究静电/共价复合物对β-胡萝卜素的传递特性，结合两类传递系统的形成机理分析造成其性能差异的原因。项目成果将为超声在蛋白-多糖复合传递系统构建中的应用奠定理论基础，对于大豆与果胶高值化利用及食品生产技术创新具有重要意义。

利用蛋白-多糖相互作用构建二元复合物是近年来设计食源性功效因子传递系统的重要趋势，但传统制备方法繁琐耗时，产品功能不理想。本项目选择大豆分离蛋白（Soy protein isolate, SPI）和果胶为研究对象，通过超声波辅助技术对原料进行改性，发现未经改性的原始果胶样品最有利于静电相互作用，而经果胶酶水解的果胶结构和经超声波-pH迁移改性的SPI可提高共价复合物得率并增强其功能特性。将超声波（630 W、10 min）应用于SPI和果胶的静电相互作用中，可显著提高静电复合物乳化特性和结构稳定性；将超声波（450 W）应用于SPI和果胶的接枝反应中，可在1小时内获得与传统干热法反应5天所得产物相当的接枝率，并显著提高共价复合物的结构与功能特性。通过研究静电/共价复合物纳米乳液对β-胡萝卜素的传递特性发现，经超声处理的复合物乳液包埋率高、在体外消化过程中保护作用强、且贮藏稳定性强。相比之下，静电复合物乳液更有利于β-胡萝卜素的控释；共价复合物乳液生物可及性更高。本项目从原料结构角度出发分析了复合物的构效关系，阐明了超声波在制备复合物反应条件、反应效率和产品结构功能特性等方面的优势及其在两种反应中的作用机理，并结合两类传递系统的形成机理分析了造成其性能差异的原因，为基于蛋白质-多糖复合物的新型食源性功效因子传递系统开发提供了研究基础。