三种方法制备的柚皮精油的 分子蒸馏及GC-MS挥发性成分测定

本研究采用冷压榨、水蒸汽蒸馏及机械磨皮三种方法制备柚皮精油,通过分子蒸馏技术将原油分离为轻、重两个组分,利用气相色谱-质谱仪(GC-MS)分别对原油及各组分进行挥发性成分分析。结果表明,三种原油中主要的挥发性物质是以D-柠檬烯为主的萜烯类物质,相对含量均在92%以上,其中冷榨原油的香气成分含量均高于其他两种原油,热蒸原油中有异味物质(氧化柠檬烯以及右旋香芹酮)生成,磨皮原油澄清度较差,因此冷榨油品质最好。分子蒸馏技术分离纯化原油后分析发现,三种精油的轻组分中萜烯类物质含量均达到99%以上,重组分中萜烯类物质含量均有不同程度的降低;其中冷榨油重组分的呈香物质相对含量最高,与原油相比,呈香物质的相对含量提升最大。热蒸油重组分中的异味成分(氧化柠檬烯)相对含量下降至0.22%,但未完全除去;磨皮油重组分中保留指数大于2000物质的含量升高至5.92%,使精油澄清度下降。综合以上分析,分子蒸馏技术能对柚皮精油具有良好的脱萜效果,并且更有利于冷榨油的脱萜和浓缩精制。

Molecular Distillation Separation and GC-MS Analysis of Pomelo Peel Oil Prepared by Three Methods

The pomelo peel oil was prepared by cold pressing,steam distillation and mechanical microdermabrasion. The crude oil was separated into light and heavy components by molecular distillation technique,and the volatile components of crude oil and each component were analyzed by gas chromatography-mass spectrometry(GC-MS). Results showed that terpenes mainly composed of D-limonene was the most important volatile components,relative content was over 92%. The cold pressed oil had no odorous substances(limonated limonene and dextrorotatory)and better clarity and stability,so the quality of cold pressed oil was better. However,after the molecular distillation treatment,the content of terpenes in the light components of the three essential oils was over 99% and heavy components decreased. Compared with crude oil,the increment of aromatic substances content of cold pressed oil was the largest,which was contributed by heavy components. The relative content of odor ingredient(limonene)of heavy components in hot steam oil was decreased to 0.22%,it was not completely removed,however. The content of substances with retention index greater than 2000 increased to 5.92%,resulting in the decline of the clarification of essential oil. Molecular distillation technology makes more use of the comprehensive processing and utilization of cold pressed oil.