白背毛木耳多糖APP3a羧甲基化修饰工艺研究

以白背毛木耳多糖APP3a为原料,用碱性氯乙酸法制备羧甲基化白背毛木耳多糖（CM-APP3a）,研究其羧甲基化的工艺。以羧甲基取代度为指标,通过单因素实验对氯乙酸用量、氢氧化钠用量、反应时间、反应温度等工艺参数进行研究,并用响应面Box-Behnken实验设计对羧甲基化工艺进行优化。实验结果表明,APP3a羧甲基修饰的最佳工艺条件为:反应介质为异丙醇,多糖APP3a 60 mg,氯乙酸用量1.45 g,氢氧化钠用量2.48 g,反应温度55℃,反应时间3.5 h。在该优化条件下,羧甲基白背毛木耳多糖（CM-APP3a）的取代度达为0.892,与理论预测值0.895相比,其相对误差为0.33%。说明通过响应面优化后得出的回归方程具有一定的实践指导意义。 

Carboxymethyl modification of Auricularia polytricha polysaccharide

Auricularia polytricha polysaccharide( APP3a) was carboxymethylated by the method of alkaline chloroacetic acid and its carboxymethylation process was studied.The process parameters including chloroacetic acid amount,sodium hydroxide amount,reaction time,temperature,were studied through the single factor(experiment,and the optimization of carboxymethylation were adopted by response surface experiments with Box- Behnken design. The experimental results showed that the optimal conditions of Auricularia polytricha polysaccharide( APP3a) carboxymethylation were obtained as follows: isopropyl alcohol used as reaction medium,60 mg of APP3 a,1.45 g of chloroacetic acid,2.48 g of sodium hydroxide,55 ℃ of reaction temperature,3.5 h of reaction time. Under this conditions the maximum substitution degree of 0.892 was obtained. Compared to the theoretical value,the relative error was 0.33%. It showed that the regression equation by response surface optimization had certain practical significance.