干燥方法对洋葱精油提取率及DPPH自由基清除活性的影响

Effects of different drying methods on extraction rate of onion essential oil and its DPPH radical scavenging activity

选用热风干燥(AD)、真空冷冻干燥(FD)和微波冷冻干燥(MFD)将新鲜洋葱制成洋葱粉,用蒸馏法提取洋葱精油,对比3种干燥方法下洋葱粉精油的提取率及DPPH自由基清除能力。结果表明,采用微波冷冻干燥洋葱粉提取洋葱精油,得率可达4.57%,且提取时间最短。洋葱精油提取的较优条件为MFD洋葱粉、温浸温度40℃、温浸时间50 min,该条件下得到的洋葱精油具有较强的DPPH自由基清除能力。

In order to improve the extraction rate of onion essential oil and make the extraction process of onion essential oil easy to operate,three drying methods,including hot air drying(AD),vacuum freeze drying(FD)and microwave freeze drying(MFD),were used to make fresh onion powder.The essential oil of onion was extracted by distillation.The extraction rate and the DPPH free radical scavenging ability of three kinds of dried onion powder were compared.The extraction rate of onion essential oil from onion powder by wave freeze-drying was 4.57%,with shortest extraction time.The optimum extraction conditions of onion essential oil were determined by orthogonal experiment,i.e.MFD onion powder,warm-extracted at 40℃for 50 min.The onion essential oil obtained under the control of these conditions has strong DPPH radical scavenging capacity.