Research of ultrasonic wave extraction of isoflavone from black soybean by response surface methodology

The ultrasonic wave extraction process of isoflavone from black soybean which occurred in Jinlin was studied. A central composite experiment of three factors and three levels, concluding liquid-solid ration, extraction time and temperature, was designed based on the results of single factor experiments. And the results were analyzed by response surface methodology with Design-expert. The optimal parameters of ultrasonic wave extraction from black soybean was liquid-solid ration of 46∶1 (mL/g) , extraction time of 51min and temperature of 52℃. Under the optimal conditions, the actual measured value of black soybean content was 1.883%, while the predicted value was 1.891%. The technical parameters of ultrasonic wave extraction process were reliable due to the small difference between the two values. Compared with the shaking extraction method, ultrasonic wave extraction process had some advantages, such as high efficient, time efficient and energy saving. The results showed that the soybean content from Jinlin in the highest and the soybean content from Shanxi was the lowest by measuring the isoflavone content from black soybean which occurred in four different areas under the optimal parameters.