Abstract: Objective: To find optimal conditions for the ultrasonic-assisted extraction conditions of water-soluble polysaccharide from mung bean hull. Methods: On the basis of one-factor-at-a-time experiments, response surface analysis (RSA) was used to optimize the extraction of water-soluble polysaccharide from mung bean hull (MWP). Results: Ultrasonic power had the greatest effect on the extraction rate of MWP, followed by pH; the effect of ultrasonic treatment time was the weakest. The optimal extraction conditions were found to be three repeated extractions at pH 4.6 and 155 W ultrasonic power for 40 min each time. Under these conditions, the extraction rate of MWP was 8.54%, showing a relative error less than 5% when compared to the theoretical value. Conclusion: This study provides a reference for the extraction of water-soluble polysaccharide from mung bean hull, and lays a foundation for future research on mung bean hull.

Key words: mung bean hull, water-soluble polysaccharide, ultrasonic-assisted extraction