淀粉储藏期老化严重影响淀粉质食品品质，添加多糖来控制淀粉的老化已成为国内外的研究热点。目前多糖对淀粉老化特性的影响规律和作用机理尚不清楚。面对海量的多糖和淀粉种类，进行系统研究探讨其规律和机理是难以实现的。本项目拟采用物理化学手段（微射流、皂化、稀酸水解和烷基化修饰）制备不同分子结构(分子量、酯化度、支链度、疏水性)的果胶为代表性多糖。采用传统化学法结合现代仪器分析表征果胶和淀粉的分子结构信息。以不同结构果胶与三种代表性淀粉（大米、马铃薯和豌豆淀粉）复配成混合体系，通过RVA和动态流变测定考察短程老化；质构、DSC和X衍射测定长程老化；渗漏直链淀粉量测定、相互作用测定、红外、水分迁移和分布测定、扫描电镜、绝对分子量表征、结合分子模拟探讨淀粉老化机理。采用主成分分析等数理统计手段分析果胶（多糖）结构对淀粉老化性质的影响规律和机理，从而促进淀粉老化理论的发展，为淀粉质食品品质改良提供理论指导。

The retrogradation of starch during storage influences starch-based products strongly. Controlling retrogradation of starch by adding polysaccharides has been a research hotspot. However, the influence law and mechanism of polysaccharides on retrogradation of starch is not clear. Considering abundance of polysaccharides and starch, it is hard to investigate the law and mechanism by a systematic study. In this project, pectins with different structural characteristics (molecular weight, degree of methoxylation, degree of branching, and hydrophobicity) will be selected as representative polysaccharides, which will be prepared by kinds of physicochemical methods such as dynamic high pressure microfluidizaiton, saponification, acid hydrolysis and alkylation. After preparation, their structure will be characterized by traditional chemical methods combing with modern instrumental analysis. Pectins with different structures will then be mixed with three representative starches (rice starch, potato starch and pea starch) respectively. Short-term retrogradation will be determined by RVA and dynamic rheology. Long-term retrogradation will be analyzed by texture analyzer, DSC and X-ray. The retrogradation mechanism will be investigated by determination of leached amylose, interaction force experiment, FTIR, determination of water migration and distribution, scanning electron microscope, HPSEC, and molecular simulation. Then mathematical statistics such as Principal Component Analysis will be applied to analysis the influence law and mechanism of pectin (polysaccharides) structure on retrogradation of starch, which will promote the development of theory of starch retrogrdation, and provide theoretical guidance for improving quality of starch-based products.