The Effect of TIME and Ultrasound Power Level on the Efficiency of Isoflavones Extraction From Soybean

This study aims to investigate the effect of time and power level of ultrasound on the efficiency of isoflavones extraction by 80% ethanol (v/v) from soybean. Total isoflavones concentration is determined with 6 isoflavone standards: daidzin, glycitin, genistin, daidzein, glycitein and genistein by High-performance liquid chromatography(HPLC) method. Using two-way ANOVA to evaluate the effects of ultrasonic timing and ultrasonic energy levels on the intake of isoflavones, the ultrasound condition selected is 70% of the power level for 15 minutes. Compared to stirring extraction (at 30oC and 70oC), and ultrasound in combination with stirring extraction, the ultrasonic method has higher extraction efficiency than the stirring method at 30oC, but lower than either the stirring method at 70oC or the ultrasound-assisted stirring method. In addition, the ultrasonic process does not affect DPPH-free radical capture, which demonstrates that the antioxidant activity of extracted compounds is not decreased