羧甲基玛咖多糖制备及抗氧化性研究

Study on the carboxymethylation of maca polysaccharide and antioxidation

通过水提醇沉淀法从玛咖粉末中提取了玛咖多糖,采用氢氧化钠-氯乙酸反应体系,以异丙醇为溶剂对玛咖多糖进行羧甲基化,经Sevage法脱除蛋白、透析得到固体羧甲基玛咖多糖,产物有良好的水溶性。紫外光谱显示羧甲基玛咖多糖水溶液在260～280nm处未见核酸和蛋白质的特征吸收峰;红外光谱表明羧甲基玛咖多糖在1600cm-1出现-COO特征吸收,并具有典型的多糖吸收峰,结构中存在β-型糖苷键;灰度法测定羧甲基玛咖多糖的取代度DS为0.618。同时抗氧化能力测定结果表明玛咖多糖羧甲基化前后均可清除利用Fenton反应由Fe2+-H2O2体系产生的羟自由基,且羧甲基化后玛咖多糖对羟自由基的清除能力增强。

Maca polysaccharide was extracted from Maca powder with hot water and precipitated with alcohol.Carboxymethyl Maca polysaccharide was prepared in NaOH-monoehloroacetic acid with isopropanol as the solvent.Sevage method was used to removing free protein,the product exhibit solubility in.In the infrared spectra,a typical of-COO at 1600 cm^-1was observed,the characteristic bands of polysaccharide was also excisted andβ-glycoside linkage was in its structure.There is no absorption peak at 260-280nm in the UV spectra.Meanwhile the degree of substitution（DS）was 0.618.The antioxidation before and after carboxymethylation showed that Maca polysaccharide was quit good in clearning hydroxyl free radical by of Fe^2＋-H2O2 system.