摘要:
采用超临界CO2萃取余甘子精油,选择萃取压力、温度、时间和甲醇添加量为因素进行正交实验,得出影响精油得率的大小次序为:萃取压力＞萃取时间＞萃取温度＞甲醇添加量,优选出超临界CO2萃取的最佳工艺条件为:萃取压力20MPa,萃取温度35℃,萃取时间3 h,甲醇添加量10 mL.在这个最佳条件下试验,余甘子精油得率为2.5，(w/w).采用DPPH自由基体系和亚油酸过氧化体系测定余甘子精油的抗氧化活性,并运用GC-MS法分析鉴定其化学成分.结果表明,超临界CO2萃取的余甘子精油具有较强的抗氧化活性,其清除DPPH自由基的活性优于维生素E和合成抗氧化剂BHA,抑制亚油酸过氧化的能力优于维生素E;从该精油中鉴定出了30种化学成分,其中主要成分为β-波旁烯(30.15，)、丁香酚(8.25，)、β-丁香烯(8.56，)、二十四醇(14.42，)及十七烷醇(2.92，),初步推断甲基丁香酚、β-丁香烯、β-波旁烯为主要的抗氧化成分.余甘子精油具有较强的抗氧化作用,可望开发成为天然食品抗氧化剂.
Abstract:
Experiments were conducted to investigate the components and in vitro antioxidant activity of the essential oils from emblica (Phyllanthus emblica L. ) fruit. The essential oils were obtained by supercritical fluid extraction (SFE) and an orthogonal array design (L9) with three factors and three levels was employed to optimize. Operating conditions. Optimum extraction conditions were: pressure 20 MPa, temperature 35℃, extract time 3h and methanol 10 mL. The essential oils were analyzed by a gas chromatograph-mass spectroscope and a total of 30 compounds accounting for 99.86% of emblica essential oils were identified. The major components were β-bourbonene, tetracosanol, eugenol, β-caryophylleneand, and 2, 3-dihydroxypropanol, accounting for 38.23%, 17. 20%, 10.94%,5. 39% and 4. 36% of the total, respectively. The antioxidant activities of the oils were evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and linoleic acid peroxidation assays. The EC50 value of the emblica essential oils for scavenging DPPH radicals (11.2±1.6 μg/mL) was higher than that of BHA and α-tocopherol, while the oils exhibited higher inhibition activity than α-tocopherol in the linoleic acid system. Methyl eugenol, β-bourbonene and β-caryophyllene might be responsible for antioxidant activities. The results suggested that emblica fruit could be a potential source of antioxidants of plant origin.
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