提取方法对葡萄柚精油性质与组成的影响

葡萄柚精油是柑橘精油的重要类别,具有清新、浓郁的特征果香,是一种广受欢迎的天然香精。为了研究提取方法对葡萄柚精油表观特征、物理性质及化学组成的影响,文章分别以蒸馏法和冷榨法制备葡萄柚精油,采用气质联用(GC-MS)分析其化学组成。结果表明蒸馏法的精油得率远高于冷榨法,但冷榨法所得精油的色泽和气味更接近天然葡萄柚,折光率和相对密度也更高;蒸馏法所得精油含有39种可检测化合物,其中含氧化合物18种,相对含量为14.11%,而冷榨法所得精油含37种可检测化合物,16种为氧化物,相对含量达17.18%,尤其是芳樟醇、葵醛、柠檬醛等特征香气成分的含量明显高于前者,表明冷榨法比蒸馏法更适宜制备高品质葡萄柚精油。

Effects of extraction methods on the properties and composition of grapefruits essential oil

Essential oil from grapefruit is an important kind of citrus essential oil,which is popular in the world as a natural fragrant agent with fresh and full-bodied characteristic fruity flavor.To investigate the effects of extraction methods on apparent properties,physical characteristics and chemical compositions of grapefruit essential oil,the oil was extracted from grapefruit peels through distillation and cold-press methods respectively,and compounds contained were detected by gas chromatography-mass spectrometry(GC-MS).Yield of essential oil from distillation method was much higher than that of cold-press.However,the color,luster and odor of oil from cold-press method were much more close to those of fresh grapefruits,and its refractive index and relative density were higher,too.There were 39 detectable compounds in the oil from distillation,including 18 oxides with a total content of 14.11 %,while 37 compounds were found in the oil from cold-press,which contained 16 oxides with their total content of 17.18 %.More importantly,the concentrations of characteristic aroma substances,such as linalool,decanal and citral in cold pressed oil,were all higher than those in distillated oil.The results indicated that cold-press method was more suitable to extract grapefruits essential oil with good quality than distillation method.