Application of response surface methodology for extraction optimization of total flavonoids from broccoli assisted by ultrasonic

Response surface methodology was used to optimize the processing conditions for the extraction of total flavonoids from Broccoli using ultrasonic extraction method.Based on the single-factor experiments,Box-Benhnken design involving three factors as independent variables was used to set up aquadratic polynomial regression equation for the yield of total flavonoids as function of ultrasonic powder,ultrasonic temperature and ethanol concentration,and each variable and their interactions effects on the yield were studied by using response surface analysis.The results showed that the optimal extraction conditions of total flavonoids from Broccoli were:the ratio of liquid-to-material 1∶20,ultrasonic powder201 W,ultrasonic temperature 53 ℃,ethanol concentration 51%,ultrasonic time 30 min.The yield of total flavonoids could be up to 1.128% under the optimal extraction condition,the relative error was 0.53% compared to the predictive value which indicate the feasible model fitted well with the experimental data.Meanwhile the extraction yield increase by32.2%compared with heat leaching process,results could provide a reference for the totalflavonoids extraction from Broccoli.