Response Surface Methodology for the Optimization of Extraction Technology of Total Flavonoids from Walnut Green Husk

Taking walnut green husk as materials,six factors including ultrasonic power,ethanol concentration,ultrasonic temperature,ultrasonic time,ratio of solid to liquid and standing time were selected,on the basis of single-factor experiments,the Box-Behnken design(BBD) was used to establish a quadric regression equation for predicting the yield of flavonoids.The results showed that the ethanol volume fraction 62%,ultrasonic temperature 51℃,ultrasonic time 31 min,standing time 6.5 min was the optimitization of extraction technology,which led to estimated and observed values of maximal yield of flavonoids of 1.080% and 1.077%,respectively.It suggested that the optimal extraction conditions were reliable.