Abstract: Purpose: To optimize the ultrasonic-assisted extraction process for water-soluble polysaccharides from Sophora japonica flower for improved extraction efficiency. Methods: The optimization strategy used was a series of one-factor-at-a-time investigations and subsequent response surface analysis based on a quadratic regression rotary combination design. Results: Within tested level ranges, the importance of four process parameters affecting extraction yield of polysaccharides from big to small was ultrasonic treatment time, liquid-to-solid ratio and ultrasonic power in turn. Ultrasonic treatment time of 58 min, ultrasonic power of 217 W and extraction temperature of 30 ℃ were found optimum for polysaccharide extraction. Conclusion: ultrasonic assistance is beneficial to shorten extraction time and improve extraction efficiency and consequently, suitable for the extraction of water-soluble polysaccharides from Sophora japonica flower.

Key words: Sophora japonica, polysaccharides, ultrasonic, extraction