山药多糖提取工艺优化及结构分析

【作者】 吴丹；

【导师】 李永泉；

【作者基本信息】 浙江大学 ， 遗传学， 2004， 硕士

【摘要】 山药(Dioscorea batatas Decme)，又名白苕、土薯、大薯、薯药，营养丰富，具有很高的药疗价值。《本草纲目》记载：山药性温、味甘平、无毒，健脾胃、益肺肾、涩精止泻；山药还具有抗衰老、抗氧化、提高应激力、增强免疫力、降血脂、抗肿瘤、抗突变等功效，山药中起到药疗作用的主要成分是山药多糖。本文主要研究山药多糖的提取工艺、分离纯化及多糖的结构分析。提取工艺主要考虑浸提水溶液温度、pH值、料水比和浸提时间对多糖得率的影响，研究最佳的粗多糖浸提工艺参数；首先进行单因素试验，在此基础上采用正交实验进行分析，进而采用中心组合设计进行中试，最后经统计软件matlab编程进行多元线性回归分析得到山药粗多糖较优化提取工艺为：pH值为9.13，料水比为1：5.5，浸提温度85℃左右，沉淀时酒精浓度70％，离心转速1900×g，所提取的粗多糖含纯多糖为20％。分离纯化从山药入手，脱除蛋白质与酒精沉淀后，采用离子交换树脂DEAE—52和Sephadex G—100进行分离，结果得到中性和酸性两种不同性质的多糖，中性多糖和酸性多糖颜色均为为纯白色。气相色谱分析表明：山药中性多糖主要由鼠李糖、木糖、甘露糖、半乳糖组成，其组成比例为8：16：25：10，酸性多糖主要由鼠李糖、阿拉伯糖、木糖、甘露糖、半乳糖组成，其组成比例为7：3：11：19：18。高效液相色谱分析可知中性多糖和酸性多糖的分子量分别为15598D和21500D；红外分析可知中性多糖和酸性多糖分别含有吡喃糖和α-糖苷键构型。浙江大学硕士学位论文馨本研究为山药多糖提纯的工业化生产提供了理论依据，为山药保健食品和药物的开发提供了良好基础。更多还原

【Abstract】 Dioscorea batatas Decme, also named Chinese yams, is important staple food in many tropical countries[1][2] . Even more interestingly, yams have also been used as health food and herbal medicinal ingredients in trational Chinese medicine [3]. Recently, several benefical properties of yams were reported in the literature. Yam extracts showed significantly antioxidative activity and modified serum lipid levels in humans [4]. Yam flour was reported to protect rats from chemical-induced toxicity [5]. The extracts of browned yam flour show antioxidative activity in model systems[6]. Dioscorin, a purified storage protein of yam, was reported to possess scavenging properties against free radicals [7]. The most useful extraction from Dioscorea batatas Decme is Dioscorea polysaccharide, so the main research works of this article are extraction technique optimization purification and structure analysis of polysaccharide. The major factors which influence the extracting ratio are saturating temperature pH saturating time and the ratio between material and water. The single factor statistical analysis was done first, then, the orthogonal array experiment was carried out. The experimental result showed that the two factors were statistically significant. Subsequently, the procedure of middle scale test was optimized by means of central composite design and the data were analyzed by theprofessional statistical software. The optimal extracting procedure was pH9.13, the ratio between material and water 1: 5.5 , under this conditions the polysaccharide purity in crude is 20% . For purification of polysaccharide, the protein should be removed from the supernatant, then, the polysaccharide was precipitated again with ethanol at the concentration of 70%. Following, ion-exchange column DEAE-52 and Sephadex G-100 column chromatography were used as the last step of isolation. At last two main polysaccharide electriferous polysaccharide and non- electriferous polysaccharide were separated form the Dioscorea batatas Decme, which can be used for structure analysis. Gas chromatogram analysis showed that the electriferous polysaccharide was made up of , non- electriferous polysaccharide was made up of, HPLC analysis testified the molecular weight of electriferous polysaccharide and non- electriferous polysaccharide are 15988 and 21500D, infrared spectrum showed that electriferous polysaccharide is a -epimers glycosidic bond, non- electriferous polysaccharide is pyranose .This research work would establish a strong basement for the applications of Dioscorea batatas Decme polysaccharide in drug industry, and also point out the efficient way to industrialized extract of Dioscorea batatas Decme polysaccharide.更多还原