茶多糖的纯化及结构分析

Purification and Structural Analysis of Tea Polysaccharide

从茶多酚生产的下脚料中,通过有机溶剂洗涤和凝胶色谱分离,得到一种水溶性多糖。经高效液相色谱分析,为单一茶多糖,其相对分子量为(10～10.5)×105;气相色谱分析表明,糖基由葡萄糖、半乳糖、阿拉伯糖、甘露糖和鼠李糖组成,其摩尔比为6.97∶5.34∶8.11∶2.76∶1.14;比色法测其总糖含量、蛋白含量、糖醛酸含量分别为90%、8.52%、27.65%。红外光谱和核磁共振分析表明,该多糖是由单糖通过β-糖苷键连接的,多糖链上络有糖醛酸、氨基或蛋白基团,同时含有α和β异头碳;x-衍射分析显示,随多糖纯度的提高,茶多糖更易结晶,且有不同的晶体聚合物出现;DSC的分析表明,随茶多糖纯度的提高,热焓增加,峰温向高温漂移。

A water soluble tea polysaccharide was obtained by washing with organic solvents and isolating with gel chromatographic separation from the byproduct of tea polyphenols. A single peak of tea polysaccharide （TPS） with the relative molecular weight （10- 10.5 ）×10^5 was identified by HPLC. The results of GC indicated that TPS consists of glucose, galactose, arabinose, mannose and rhanose with a molar ratio of 6.97 ： 5.34 ： 8.11 ： 2.74 ： 1.14 ; the content of total saccharide, protein and acid polysaccharide were 90% , 8.52 % and 27.65 % , respectively. The result of IR and ^13C NMR showed that TPS was composed of monosaccharide linked by p-glycosidic bond, there were uronic acids, amido or proteinic groups and α and β isomer in the polysaccharide chain. The analysis of x-diffraction indicated that TPS easity crystallized and formed the different crystallization as raising the purification of TPS. The analysis of DSC showed that the enthalpy and the peak temperature of TPS increased with the purification.