为了简便高效的制备出壳寡糖,采用过氧化氢(质量分数1.0%)来降解稀醋酸溶液(质量分数1.0%)中含量为3.5%的壳聚糖,60℃下摇床反应4.5 h后得到壳寡糖水溶液,检测溶液中还原性端基数并估算降解物平均聚合度来表征降解程度.降解液浓缩到25%,调pH 7.0,用体积分数95%乙醇分级沉淀分离壳寡糖可以除掉部分单糖,总的回收率达93.0%.通过电喷雾电离质谱(ESI-MS)分析,3倍醇沉出的产物为2-4糖为主的壳寡糖产品.实验说明过氧化氢氧化降解壳聚糖可制取聚合度为2-4的壳寡糖.%Low molecule weight ehitosan oligosaccharide (COS)was prepared by degraded 3.5% chitosan in 1.0% acetic acid with 1.0% hydrogen peroxide at 60℃ shaking for 4.5 hours. Concentration was then adjusted to 25%, pH 7.0. The solution finally was precipitated by 95% alcohol and COS was obtained without monosaccharide at the yield of 93.0%. The molecular weight was estimated by Fehling oxidation-reduction titration which was detecting the average value of the reducing ends. The distribution of COS was analyzed by electro-spray ionization mass spectro-motry (ESI-MS). The COS comprised mainly of 2 to 4 chitosan oligosaccharides was precipitated by three volume of alcohol. The conclusion was that COS could be efficiently prepared by the hydrogen peroxide oxidation of chitosan.
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