Abstract:

An optimized ultrasonic-assisted procedure was proposed for the exhaustive extraction of superoxide dismutase
(SOD) from “Ming” mung bean, a famous cultivar in Mingguang, Anhui province. Seven operating parameters were
screened for their effects on the specific activity of SOD using Plackett-Burman design, and solvent-to-solid ratio, phosphate
buffer pH and ultrasonic-waterbath temperature were identified as the most significant variables. Subsequently, the levels
of the three variables were optimized by response surface methodology. The optimal extraction conditions for SOD were
determined as phosphate buffer at pH 7 as the extraction solvent with a solvent-to-solid ratio of 22:1 (mL/g), waterbath
extraction at 44 ℃ with an ultrasonic power of 140 W for 20 min and subsequently at 60 ℃ for additional 1.5 h without
ultrasonication. Under these conditions, the specific activity of SOD was 856.95 U/mg. “Ming” mung bean as a new source
of SOD contained more abundant SOD when compared with the traditional sources.

Key words: “Ming&rdquo, mung bean, SOD, ultrasonic-assisted extraction, Plackett-Burman design, response surface methodology