Optimization of microwave extraction condition of Gynura divaricata polysaccharide by response surface analysis

Gynura divaricata polysaccharide was extracted from Gynura divaricata with the method of microwave-assisted extraction. Based on the results of single factor experiments, the extraction process was optimized by response surface analysis. The results indicated that the influencing factors during extraction were: liquid-solid ratio, microwave time, and microwave power, among which the influence of liquid-solid ratio was the most significant. The optimal conditions were as follows: liquid-solid ratio of 45∶1(mL/g), microwave power of 390 W, microwave time of 22 min. Under optimal extraction conditions, the extraction rate of Gynura divaricata polysaccharide was 15. 36%, which was pretty close to the predicted result. The optimized response surface methodology had some practical value for the process.