Comparison of the optimal extraction process of rutin from buckwheat by orthogonal and response surface design experiments

In order to obtain the optimal extraction process and guide the experiment design,the process conditions of ethanol reflux were investigated by orthogonal and response surface method. The effects of extraction time,temperature,the ratio of liquid to materials and ethanol concentration on the extraction rate were discussed. The results show that the two methods obtained the same result,which is extraction timeethanol concentrationtemperaturethe ratio of liquid to materials. The optimal process obtained by orthogonal design is extraction time 120 min,temperature 90 ℃,the ratio of liquid to materials 1∶30,and ethanol concentration 100%;while that by response surface method is extraction time 114 min,temperature 86 ℃,the ratio of liquid to materials 1∶32,and ethanol concentration 96%. Verification testing results indicate that the extraction rate under the optimal process of response surface method is 6.91% higher than that of orthogonal design. Therefore,the optimal process was decided according to response surface method,under which the extraction rate can reach 0.3452mg/g.