甘薯多糖SPP-Ⅰ的制备与结构初步研究

Study on preparation and structure of sweet potato polysaccharide SPP-Ⅰ

研究采用水提醇沉法提取甘薯粗多糖,进行单因素试验考察,用正交法优化工艺.再经DEAE-纤维素-52阴离子交换柱和SephadexG200凝胶柱对所得粗多糖进行层析纯化,得到甘薯多糖组分SPP-Ⅰ.应用苯酚硫酸法测定多糖百分含量,HPLC法测定多糖分子质量,紫外光谱、红外光谱、甲基化衍生结合GC-MS分析多糖结构.结果表明甘薯多糖最优提取工艺为提取温度90℃,提取时间3h,液料比40∶1,提取次数3次.甘薯多糖SPP-Ⅰ总糖百分含量分别为97.61%,分子质量为245ku,紫外光谱扫描结果显示无核酸和蛋白质吸收峰,红外光谱扫描结果表明含有多糖类物质的特征吸收峰,结合甲基化和GC-MS分析初步确定甘薯多糖SPP-Ⅰ是具有1→3、1→3→6糖苷键结构的α-葡聚糖.

Crude polysaccharides were extracted from sweet potato by hot water extraction and alcohol precipitation,single factor test and orthogonal method was carried out to optimize process.DEAE cellulose 52 and Sephadex G-200 gel filter column chromatographies were sequentially used to purify crude polysaccharides,and the purified polysaccharides SPP-Ⅰwere obtained.The content of the polysaccharide components of SPP-Ⅰwas determined by phenol sulfuric acid method,the molecular weight was analyzed by high performance liquid chromatography(HPLC),the structure was analyzed and characterized by ultraviolet(UV)spectroscopy,infrared(IR)spectroscopy and gas chromatograph mass(GC-MS).The results showed the optimized extration exprocess was as follows:extraction temperature at 90℃,extraction time for 3 h,liquid-solid ratio at 40∶1,extraction times for 3 times.And the total sugar content of SPP-Ⅰwas 97.61%,the molecular weights were 245 ku.The structural analysis demonstrated that SPP-Ⅰwas composed ofα-glucan with 1→3 and 1→3→6 linkage.