不同干燥处理对马齿苋总酚含量及其抗氧化性的影响

分别采用热风干燥法、真空微波干燥法和真空冷冻干燥法处理马齿苋,测定马齿苋粉甲醇提取液的总酚含量、总抗氧化能力、还原能力、DPPH·清除能力、羟自由基清除能力和超氧阴离子自由基清除能力,研究不同干燥方法对马齿苋粉总酚含量和抗氧化性的影响。结果表明,真空冷冻干燥法制得的马齿苋干粉样品中总酚含量显著高于真空微波与热风干燥样品;不同的干燥方法对马齿苋粉的抗氧化性有明显影响,真空冷冻干燥法制得的马齿苋粉甲醇提取液的总抗氧化能力、还原能力、DPPH·与羟自由基清除能力显著高于真空微波和热风干燥法制得的马齿苋粉(P0.05),但真空冷冻干燥样品与真空微波干燥样品对O_2~-·的清除率无显著差异,综合考虑产品品质与加工成本,采用真空微波干燥法更为合理。

Effects of Different Drying Methods on Total Phenols Content and Antioxidant Properties of Purslane Powder

To investigate the effects of drying methods on the total phenolic contents and antioxidant properties of purslane powder, hot air drying, vacuum microwave drying and vacuum freeze drying were applied in the drying processing of purslane, and the methanol extracts from purslane powder were determined for total phenolic contents, total antioxidant capacity, reducing capacity, DPPH free radical scavenging capacity, hydroxyl radical(·OH) scavenging capacity and superoxide anion (O2-·) scavenging capacity. The results showed that, the total phenols contents of the samples from the vacuum freeze drying were significantly higher than the samples from vacuum microwave drying and hot air drying method. The antioxidant properties of purslane extracts were influenced significantly by drying methods, vacuum freeze dried purslane extracts exhibited higher total antioxidant activity, reducing activity and free radical scavenging activity against DPPH·and·OH than the other extracts. However, no obvious difference between vacuum freeze dried extracts and vacuum microwave dried extracts in scavenging O2-· capacity was observed. And considering product quality and cost, vacuum microwave drying was recommended to be the most reasonable drying method.