橄榄多酚的超声波-微波提取工艺优化及其抗氧化活性研究

Optimization of Ultrasonic-Microwave Extraction Technology and Antioxidant Activity of Olive Polyphenols

以橄榄鲜果为实验原料,选取超声时间、超声功率、微波时间、乙醇浓度和液固比做单因素实验,筛选出具有显著差异的单因素进行响应面实验,优化超声波-微波协同提取橄榄多酚的工艺,最后探究橄榄多酚提取液对2,2-二苯基-1-苦肼基(DPPH)自由基、羟基自由基(·OH)以及超氧阴离子自由基(·O_(2)^(-))的抗氧化活性。结果表明,超声功率、微波时间以及乙醇浓度3个单因素对橄榄多酚得率有显著影响;采用响应面分析法得到橄榄多酚最佳提取工艺:超声功率374 W、微波时间3 min、乙醇体积分数70%,在此条件下得率为15.631 mg/g。将此工艺提取的橄榄多酚提取液进行抗氧化活性研究,结果显示其清除上述自由基的EC_(50)值分别为0.01、0.12 mg/mL和0.08 mg/mL,表明橄榄果提取液具有较强的抗氧化活性,可作为天然抗氧化剂的来源。

In this study,fresh olive fruit was used as raw material and ultrasonic time,ultrasonic power,microwave time,ethanol concentration and liquid-to-solid ratio were selected for single factor experiment.Single factors with significant differences were selected for response surface test to optimize the ultrasonic microwave synergistic extraction technology of olive polyphenols.Finally,the antioxidant activity of the olive polyphenol extract were evaluated using 2,2-diphenyl-1-picrylhydrazyl(DPPH)radicals,hydroxyl radicals(·OH)and superoxide anion radicals(·O_(2)^(-))assay.These results showed that three single factors,including ultrasonic power,microwave time and ethanol concentration,had significant effects on the yield of olive polyphenols.Using response surface analysis,the optimal extraction process for olive polyphenols was as follows:ultrasonic power 374 W,microwave time 3 min and ethanol concentration 70%,the extraction rate of olive polyphenols reached 15.631 mg/g.Moreover,the EC_(50) vales of antioxidant activity of olive polyphenols examined by DPPH,·OH and·O_(2)^(-)were 0.01,0.12,0.08 mg/mL respectively.These results indicated that olive polyphenols have strong antioxidant capacity,which could be one of the candidate resourses for natural antioxidants.