不同脱乙酰度蚕蛹壳聚糖结构分析及其清除自由基能力的比较研究

Structural characterization of different deacetylated degree chitosan from silkworm chrysalis residue and its scavenging free radical abilities

首次采用无水乙醇浸泡辅助脱乙酰基与间歇式碱处理相结合的方法,通过控制反应时间制备不同脱乙酰度的蚕蛹壳聚糖。同时对其脱乙酰度、表观黏度和分子量等理化指标进行测定,用红外光谱对其基本结构进行表征,并分别采用邻二氮菲-Fe2+氧化法、核黄素-光-氮蓝四唑法和DPPH法对其清除羟自由基(·OH)、超氧阴离子自由基(O2-·)和DPPH自由基能力进行了测定。结果表明:当反应时间为5、7、9h时,蚕蛹壳聚糖的脱乙酰度分别为:78.12%、86.45%、95.96%;蚕蛹甲壳素和不同脱乙酰度壳聚糖的红外光谱图的不同说明其结构上的差异,可为进一步研究其性质提供理论参考;蚕蛹壳聚糖对羟自由基和超氧阴离子自由基的清除率均较低,但均高于虾蟹壳来源的壳聚糖;对DPPH·的清除率较高。三种壳聚糖对三种自由基清除率的大小顺序均为:脱乙酰度为95.96%的壳聚糖>脱乙酰度为86.45%的壳聚糖>脱乙酰度为78.12%的壳聚糖。

By controlling treatment time,different deacetylated degree chitosan was prepared from silkworm chrysalis chitin with a method combining absolute alcohol soaktime with intermittent type treatment to deacetylate for the first time.The deacetylated degree,apparent viscosity,molecular weight and some relevant typical properties of products were determined.Their basic constitution was charactered by FTIR.1,10-phenanthroline-Fe2＋oxidative assay,riboflavin photodegradation--NBT reduction method and DPPH method were used to evaluate scavenging abilities of chitosan to free radical including hydroxyl radical,superoxide anion radical and DPPH radical.The results were as follows：when treatment time were 5,7,9h,deacetylated degree of chitosan were 78.12%,86.45%,95.96%,respectively.Infrared spectrogram of chitin and different deacetylated degree chitosan had significant difference,which could provide some reference for properties and application research of products.Scavenging rate of different deacetylated degree chitosan from silkworm chrysalis to hydroxyl radical and superoxide anion radical were low,but were higher than that of chitosan from shrimps and crabs.Scavenging rate of different deacetylated degree chitosan to DPPH radical was high.The orders of scavenging rate of different deacetylated degree chitosan from silkworm chrysalis to three free radicals were chitosan whose deacetylated degree was 95.96%chitosan whose deacetylated degree was 86.45%chitosan whose deacetylated degree was 78.12%.