The simultaneous microwave-assisted ethanol reflux extraction of flavonoids and saponins from Astragalus was studied. Response surface methodology (RSM) was used to develop predictive models for simulation and optimization of the extraction process. Based on the single factor test, the multivariate regression equation was obtained by the RSM of five-factors and five-levels, which designed from the Central Composite Circumscribed Design program. The response surface and contour lines were determined by using the yields of Astragalus flavonoids and saponins as response values. The optimum conditions of the microwave-assisted ethanol reflux extraction were obtained as follows: liquid to solid ratio of 22 mL/g, extraction temperature of 62°C, ethanol concentration of 64% (v/v), extraction time of 22 min, and microwave power of 590 W. The yields of Astragalus flavonoids and saponins reached as high as 25.63% and 0.98%, respectively. Multiple regression equation is extremely significant for the prediction of practical production.
2016 by Japanese Society for Food Science and Technology