Optimization of Ultrasonic-assisted Extraction of Total Flavonoids from Episperm of Lotus Seed by Response Surface Methodology

The response surface methodology is used to optimize the ultrasonic-assisted extraction of total flavonoids from episperm of lotus seed. On the basis of single factor experiments,the ethanol/water solution,solid-to-liquid ratio,extraction time,and ultrasonic power on the extraction yield of flavonoids are effects. A regression model for the yield of flavonoids is established using a Box-Behnken design involving the above four factors at three levels. The optimal extraction conditions are as follows:the ethanol/water solution is 70%,solid-to-liquid ratio of 1∶50,extraction time of 35 min,and ultrasonic power is 125 W. Under these conditions,the extraction yield of flavonoids is 14.48%,closed to predicted yield of 14.92%. This model is reliable and optimal extraction conditions are highly efficient.