摘要:
Distillation time was one of the important factors to affect the oil yield and main chemical composi-tions of Eucalyptus citriodora.The qualitative and quantitative analysis of different distillation time of volatile oil from 25-year-old E.citriodora were conducted by gas chromatography and gas chromatography-mass spec-trometry(CG-MS). Results showed that when the distillation time was 2.0 h,the oil yield(fresh leaves) was 1.220% and 42 compounds were identified.The main compounds which the relative content was more than 1.000% were citronellal(58.188%),citronellol(12.959%),neoisopulegol(8.959%),citronellyl acetate (7.686%),p-menthane-3,8-diol(3.062%),1,8-cineole(1.665%),and isopulegol(1.005%). Those 6 compounds accounted for 93.524% of citriodora oils. GC results of volatile oil from 15-year-old E. citriodora indicated that when the steam consumption was 90 mL/min and the solid-liquid ratio was 1:1.8,the oil yield was 1.156% in 1.0 h.And the content of citronellal in volatile oil was 79.966%,the total content of neoisopulegol and isopulegol was 9.313%. The characteristic components of the citriodora oil met the GB/T 22179-2008 standard.The volatile oil became less with the extension of distillation time.It was suggested that the distillation time should be 1.0 h for the good quality of citriodora oil in order to reduce energy consumption and meet the national standard.%蒸馏时间是柠檬桉(Eucalyptus citriodora)叶油出油率及其化学成分的重要影响因素之一.采用GC-MS、GC对不同蒸馏时间收集的25年生柠檬桉叶油进行定性和定量分析,研究结果表明,柠檬桉叶油水蒸气蒸馏0~2.0 h,得油率为1.220%(鲜叶得油率),柠檬桉叶油中共检测出42种化合物,其中相对含量在1.000 %以上的共计6种,分别为香茅醛(58.188%)、香茅醇(12.959%)、新异胡薄荷醇(8.959%)、乙酸香茅酯(7.686%)、对(孟)烷-3-8- 二醇(3.062%)、1,8-桉叶素(1.665%)和异胡薄荷醇(1.005%),占挥发油含量的93.524%.对15年生柠檬桉挥发油GC结果显示,当蒸汽量90 mL/min,料液比1:1.8,蒸油时间在0~1.0 h得油率为1.156%,得到的挥发油中香茅醛含量为79.966 %,新异胡薄荷醇和异胡薄荷醇含量为9.313%,柠檬桉油特征组分符合GB/T 22179-2008要求.随着蒸馏时间的延长,得到的挥发油相对较少,为了降低能耗,提取的柠檬桉油特征组分符合国家标准,建议工业上将蒸油时间控制在1.0h.