微波场协同萃取剂对大豆种皮多糖凝胶及乳化特性的调控机制

As for the microwave-assisted extraction technology of polysaccharides, scholars mainly focused on the extraction efficiency, less investigate was take care of that the effect of extraction conditions on the polysaccharide characters. Applicants have found that microwave-assisted extraction time and temperature, extraction solvent showed great impact on gelation properties and emulsification of soy hull polysaccharides. And the related mechanism is not clear. It was speculated that the synergistic effect of microwave and extraction solvent changed the soy hull polysaccharides fine structure, thereby affecting the its functional properties. So in this project, we firstly explore the role of microwave extraction system conditions on the properties of the soy hull polysaccharides by constructing gel and emulsion system, and then molecular structure characters including molecular weight distribution, lipophilic groups and chain conformation were analyzed. With the rheology methods, confocal microscopy and dynamic analysis of drop shape analysis techniques, the gelation properties of soy hull polysaccharides induced by cation and oil - water interface adsorption characteristics were made clarity. Through the analysis of the relationship between structure and properties of polysaccharides, intrinsic link between extraction conditions, structural characteristics of polysaccharides and gelation properties, emulsification will be stated. This study aims to enrich the theoretical basis of microwave-assisted extraction technology, while providing theoretical guidance for fine regulation of industrial production for series soy hull polysaccharides.

目前国内外学者主要关注微波辅助萃取多糖技术的提取效率，较少探讨萃取工艺条件对多糖性质的影响。申请人前期研究发现，微波辅助萃取时间和温度、萃取剂种类对大豆种皮多糖的凝胶性及乳化性影响很大，而相关机制尚不明确。因此本项目首先设计微波作用条件和萃取剂组成，同时构建多糖的凝胶和乳化体系，探讨制备条件对多糖性质的影响规律；然后解析不同大豆多糖分子构成、单糖组成、酰胺化度、亲油基团分布规律及分子链构象等结构特征，借助流变分析、原子力显微方法、扫描电镜和激光共聚焦显微技术明晰多糖阳离子诱导凝胶规律，利用界面流变技术和动态滴形分析考察多糖在油-水界面上的吸附特性。通过解析萃取条件、多糖结构特征与其凝胶性、乳化性之间的内在联系，明确微波场协同萃取剂对多糖的阳离子诱导响应及多糖在油/水界面吸附特性的调控机制。本研究旨在丰富微波辅助提取多糖技术的基础理论，同时为工业化生产系列大豆多糖的精细调控提供理论指导。

项目背景及研究内容：本项目基于前期研究发现，微波辅助萃取时间和温度、萃取剂种类对大豆种皮多糖的凝胶性及乳化性影响很大，为明晰相关机制，通过设计微波作用条件和萃取剂组成，构建不同的多糖的凝胶和乳化体系，探讨制备条件对多糖性质的影响规律；进一步解析不同大豆多糖结构特征，借助流变分析、原子力显微方法、扫描电镜和激光共聚焦显微技术明晰多糖阳离子诱导凝胶规律，利用界面流变技术和动态滴形分析考察多糖在油-水界面上的吸附特性。通过解析萃取条件、多糖结构特征与其凝胶性、乳化性之间的内在联系，明确微波场协同萃取剂对多糖的阳离子诱导响应及多糖在油/水界面吸附特性的调控机制。.重要结果及重要数据：通过课题组努力钻研，阐述了不同环境条件获得的大豆种皮多糖在阳离子体系中的构象演变及流变学性质，揭示了大豆种皮多糖分子构象-阳离子多糖相互作用-流变学性质之间的关系和规律。对比分析了不同环境条件获得的多糖在油/水界面的吸附特性，探讨了多糖结构-油/水界面吸附特性-乳化性质之间的关系和规律，揭示微波协同萃取条件对其吸附的影响机制。从分子量、一级结构和高级结构等方面探讨影响多糖凝胶力学及乳化特性的结构特性。在柠檬酸钠辅助萃取条件下获得的大豆种皮多糖分子链构象呈现球形，其乳化机制类似于Pickering乳液机制，同时多糖分子链的柔性，形成蠕虫状链，在乳液体系中形成了弱凝胶网络，维持体系的乳化稳定性。另外大豆种皮多糖在不同环境条件的微波场下发生不同程度的降解，从而改善其乳化性；不同提取溶剂在微波作用下，改变了多糖中蛋白结合率及分布规律，进而影响了多糖的界面活性及凝胶性。.科学意义：本研究丰富了微波辅助提取多糖技术的基础理论，为工业化生产系列大豆多糖的精细调控提供了理论指导。