果胶酶降解壳聚糖工艺优化及特性动态变化分析

Optimization of Degradation Conditions of Chitosan with Pectinase and Dynamic Change during Degradation

通过正交试验对果胶酶水解壳聚糖的工艺进行优化,并对降解过程中粘度、还原糖生成量、平均分子量等指标的动态变化进行研究。结果表明,果胶酶在50℃、pH值4.5、酶用量与壳聚糖质量之比为3、壳聚糖脱乙酰度为80%时对壳聚糖降解效果最佳,其中底物脱乙酰度对酶解效果影响极显著。在最适条件下,果胶酶对壳聚糖水解约1h,可控制产物平均分子量在2500左右。果胶酶降解壳聚糖的起始速度非常快,反应30min后粘度下降基本平稳;水解反应进行135min后,产物还原糖生成量逐渐趋于平稳。

The paper deals with optimization of degradation condition of chitosan with aid of pectinase by orthogonal test and the changes of viscosity decrease percentage and reduced sugar during degradation were studied. The results showed that the optimal conditions for degradation of chitosan with pectinase were 50℃, pH 4.5, 3 of ratio of pectinase/chitosan, 80% of degree of deacetylation（D. D）. The effect of D. D of substrate on enzymic degradation was remarkably great. Pectinase could validly degrade chitosan of 70% D.D. When chitosan was hydrolysed for 1 h in the optimum conditions, mean molecular weight could be controlled to be about 2 500. Pectinase degraded quite fast in initial reaction. After 30 min, Rη became basically stable. After 135 min, content of reduced sugar also tends to be stable.