Optimization of ultrasonic-assisted extracting polyphenols from the hemerocallis fulva

To study the optimal conditions for the ultrasonic extraction technology of polyphenols from the hemerocallis fulva. The content of polyphenols was calculated with the gallic acid as the reference standard.Ultrasonic power, solid to liquid ratio, ethanol concentration and ultrasonic time were chosen as main factors in orthogonal test, and the result was done with analysis of variance and multiple comparisons. The results showed that the main extraction influence factors of hemerocallis fulva polyphenols in turn were solid to liquid ratio, ethanol concentration, ultrasonic time and ultrasonic power. Through the analysis of variance, the three single factor of solid to liquid ratio, ethanol concentration and ultrasonic power differences were extremely significant, the ultrasonic power was not significant. Obtained by multiple comparison, ultrasonic power of 120 W, solid to liquid ratio of 1∶20, ethanol concentration of 90% and ultrasonic time of 40 min was the best extraction condition. Under the optimum conditions, the extraction ratio of hemerocallis fulva polyphenols could reach 2.975%.