芥菜多糖的研究

采用Sevag法除蛋白和乙醚除脂,再水煮-醇沉法,从芥菜中提取得到浅黄色芥菜粗多糖.苯酚-硫酸法测定总糖含量;UV法及IR法检测多糖性质;自动旋光仪测定旋光度;HPLC鉴定多糖的单糖组分及其相对百分比含量;采用凝胶渗透色谱-激光光散射联用技术(SEC-LLS)分析多糖的分子量范围及其分布.该芥菜多糖,无甜味,易溶于水,总糖含量为98.96%;192 nm处有明显吸收峰,260,280 nm处无吸收峰,证明被测物为多糖,且不含核酸及蛋白质;红外吸收光谱分析,在3 402,2 926,2 853,1 636,1 400,1 385,1 326,1 125,757,658,619,559 cm-1处表现为典型的多糖吸收峰;旋光度为 151.5°.糖残基间的苷键可能为α-糖苷键;分子量在1.42×104～2.55×106之间,80%的组分集中在2.1×105左右;芥菜多糖主要由葡萄糖、果糖、半乳糖、阿拉伯糖和木糖组成,其摩尔比值为21.4:12.89:5.6:4:2.5.

Study on the Mustard of Polysaccharides

The objective of this study is to isolate and purify the polysaccharides fractions from mustard and to determine the constituent characters. Hot water extracting and ethanol precipitating method were employed to isolate polysaccharides. After the removal of protein by Sevag method, the purified mustard polysaccharides were dried by frozen drier. The amount of total carbohydrates of mustard polysaccharides was measured with phenol-sulfuric acid method. IR spectrometry, UV-spectrophotometer, and automatic spectropolarimeter were used to determine the characteristic absorption and optical rotation of the polysaccharides, respectively. Size exclusion chromatography with laser light scattering technology was employed to measure the molecular masses. The monosaccharides contained in the mustard polysaccharides were analysed by HPLC. The amount of total carbohydrates in mustard polysaccharides is 98.96%. The molecular weight distribution was 1.42 x 10(4)-2.55 x 10(6), and eighty percent was distributed in 2.1 x 10(5). The monosaccharide constituent of mustard polysaccharides were glucose, fructose, arabinose, galactose and xylose, and their molar proportions are 21.4 : 12.89 : 5.6 : 4.1 : 2.5, respectively.