Abstract: Objective: Ultrasonic treatment was introduced to the ethanolic extraction of antioxidants from the fruiting body of Flammulina velutipes with the aim of enhancing cell disruption, and the extraction process was optimized by response surface methodology. Methods: For the evaluation of the ability of extract to scavenge free radicals, a DPPH free radical system was constructed. Ethanol concentration, ultrasonic power and extraction time were selected as major factors that influence DPPH radical scavenging ratio, and the pairwise interactive influences of the three factors at three levels on DPPH radical scavenging ratio were probed by response surface analysis. According to the results of canonical analysis, the optimum conditions for the extraction of antioxidants with high DPPH radical scavenging activity were using 95% ethanol for 20.24 min extraction under the assistance of ultrasonic treatment at 40 kHz and 400 W. The extract under these conditions presented a DPPH radical scavenging ratio of 85.32%. Conclusion: Ultrasonic treatment is helpful to extract highly DPPH radical scavenging antioxidants. Response surface methodology has good feasibility to be used as a mathematical approach to optimize process parameters for the extraction of antioxidants from the fruiting body of Flammulina velutipes.

Key words: Flammulina velutipes, antioxidant, ultrasonic, response surface analysis