Study on Optimization of Ultrasonic-assisted Extraction of Antioxidants from Portulaca oleracea L.

[Objective]To study the optimum extraction technology of antioxidants from Portulaca oleracea L. [Method]On the basis of single-factor experiment,the effects of ethanol concentration,solid-liquid ratio,extraction time and extraction times on scavenging rate of DPPH radical were inspected. According to the experimental design principles of Box-Benhnken,a four-factor and three-level response surface modeling ( RSM) was adopted to study the ultrasonic extraction technology of antioxidant from Portulaca oleracea L. [Result]Based on analyzing the significance of each factor and their interactions,the optimum extraction conditions were determined as follows: the ethanol concentration was 68%,solid-liquid ratio was 1∶ 22 g /ml,extraction time was 44 min and extraction times was 3. Under the optimized conditions,the actual scavenging rate of DPPH free radical was 0. 911 7,close to the theoretical value of 0. 913 501. [Conclusion]The ultrasonic method had the advantages of high extraction rate, short time and low ultrasonic power,therefore it could be the method for extracting antioxidant compounds from Portulaca oleracea L.