虫草花多糖提取工艺优化及其抗氧化特性

采用超声辅助法提取虫草花多糖，在单因素试验的基础上，通过L9（34）正交试验优化了虫草花多糖提取工艺；并就虫草花多糖对羟基自由基（·OH）、1,1-苯基-2-苦肼基（DPPH）自由基的清除作用和还原能力进行研究。结果表明：虫草花多糖最佳提取工艺条件为超声功率300 W，液料比30∶1（mL∶g），超声时间30 min，超声温度45 ℃。在此优化条件下，多糖的平均提取率为3.88%。抗氧化活性试验结果表明，虫草花多糖质量浓度在2.9～14.7 mg/L范围内，随着虫草花多糖质量浓度的增加，其OH、DPPH自由基清除能力及还原能力均逐渐增强，虫草花多糖质量浓度为14.7 mg/L时，对·OH和DPPH·清除率分别达到44.39%和56.34%，说明虫草花多糖具有较强的抗氧化活性。

Extraction technology optimization and antioxidant activity of polysaccharides in Cordyceps militaris

The polysaccharides in Cordyceps militaris were extracted by ultrasound-assisted extraction. Based on the single factor experiments, the extraction technology of polysaccharides in C. militaris was optimized by L9(34) orthogonal experiments. In addition, the scavenging effect of polysaccharides in C. militaris on hydroxyl radical (·OH) and 1,1-phenyl-2-picrylhydrazine (DPPH) radical and reducing capacity were also studied. The results indicated that the optimum extraction conditions of polysaccharides in C. militaris were ultrasonic power 300 W, liquid to material ratio 30∶1 (ml∶g), ultrasonic time 30 min, temperature 45 ℃. Under the optimal conditions, the average extraction rate of polysaccharides was 3.88%. The results of antioxidant activity experiments showed that when the polysaccharides concentration in C. militaris was in the range of 2.9-14.7 mg/L, the scavenging effect of polysaccharides in C. militaris on ·OH and DPPH· and reducing capacity enhanced with the increase of concentration. When the mass concentration of polysaccharides in C. militaris was 14.7 mg/L, the clearance rates of ·OH and DPPH· were 44.39% and 56.34%, respectively, which indicated that the polysaccharides in C. militaris had strong antioxidant activity.