南瓜皮多糖PP1的提纯、组分分析及原子力显微镜技术观测研究

Extraction,Purification and Properties of Pumpkin Peel Polysaccharide PP1

采用热水浸提法及十六烷基三甲基溴化铵法(CTAB法)提取南瓜皮多糖PP1,紫外分光光度法和高效液相色谱法检测纯度,红外光谱分析其结构及气相色谱测定南瓜皮多糖PP1的单糖组分;通过乙醇固定、Ni2+搭桥固定两种制样方法,原子力显微镜(AFM)观测南瓜皮多糖PP1微观形貌。结果表明:热水浸提及CTAB法分离纯化南瓜皮多糖PP1的纯度较高,不含核酸及蛋白质,红外光谱分析证实南瓜皮多糖PP1具有糖类物质的特征吸收峰,存在吡喃环,由果糖、阿拉伯糖、葡萄糖和半乳糖组成,物质的量比为0.92:2.76:5.52:2.24,AFM观测其结构呈单链形排列,无分支状结构,采用乙醇固定法得到的多糖结构形态较细长,Ni2+搭桥固定法得到的多糖结构形态相对短粗。

A polysaccharide from pumpkin peel,named as PP1,was extracted by hot water extraction method and purified by cetyltrim-ethlammonium bromide（CTAB） method.UV spectroscopy and HPLC were both used to analyze its purity,and its structure and monosaccharide composition were analyzed by IR spectroscopy and GC,respectively.The microstructure of PP1 was observed under an AFM based on fixation with ethanol or Ni2＋.The results showed that PP1 was highly pure and contained neither nuclear acid nor protein.IR spectroscopic analysis indicated that PP1 had characteristic absorption peaks of polysaccharides and pyran ring.Its monosaccharide composition was composed of fructose,arabinose,glucose and galactose at a molar ratio of 0.92：2.76：5.52：2.24.AFM observations showed that its structure was a single chain with no branches.PP1 had a long thin structure when fixed with ethanol but a short fat structure when fixed with Ni2＋.