Study Of Extraction Methods Of High Fidelity And Efficiency For Aromatic Components Of Plant

Volatile oils, also known as essential oils, which are volatile and water immiscible, are a class of oily liquid which are present in the body of plant. It is important to study the components of the volatile oil. Because of the complexity and heat-sensitivity of volatile oil components, they are easy to occuring oxidation, degradation and hydrolysis reactions in the extraction process. Also, different results may be obtained when different extracting methods are used to extract the same one volatile oil because every method has its own features. This is not inconvenient for the research of Chinese medicine. Therefore, accurate and fast extraction volatile oil methods are one of important issues for the study of traditional Chinese medicine.Microwave as a new source of heating, the extraction of essential oil with microwave assisted extraction which uses the microwave interior heating characteristics has the advantages of rapidity, efficiency, et al. However, the compounds of essential oil may be changed in the course of extraction because microwave is an electromagnetic wave. In this thesis, the essential oil of Illicium verum Hook. f., Zanthoxylum bungeanum Maxim, et al, would be extracted by Blowing Extraction at normal temperature and pressure and the Solvent Free Microwave Extraction. The extraction mechanism of Blowing Extraction at normal temperature and Solvent Free Microwave Extraction were investigated. The effective factors which may lead the essential oil compounds to change were discussed. The main contents of this thesis include the following parts:Firstly, the Blowing Extraction method at normal temperatures and pressures was used for the study of limonene. The influence parameters of extraction including the flowing rate of gas, cooling methods, collecting methods, were investigated. Under the optimized experimental conditions, the method was used for the extraction of several traditional Chinese medicine and the applicability for other kinds of Chinese medicines was studied. The results show that the Blowing Extraction method at normal temperatures and pressures were suitable for the extraction of volatile oil in the Fresh Chinese medicine with high water content or dried Chinese with high oil content.Secondly, Blowing Extraction method was used to for the extraction of essential oil of Illicium verum Hook. f., Zanthoxylum bungeanum Maxim. The influence parameters of extraction were investigated. The experimental results show that extraction efficiency and the extraction rate of essential oil of Illicium verum Hook. f., Zanthoxylum bungeanum Maxim were all increased with the increasing of temperature. Also, extraction volume, extraction efficiency and extraction rate of essential oil of Illicium verum Hook. f. were increased with the increasing of gas-flowing rate, and extraction time.Thirdly, Essential oil of Z. schinifolium Sieb. et Zucc was extracted by microwave assisted Blowing Extraction at normal temperatures and pressures. The results show that more essential oil can be obtained and its chemical composition was changed. The GC-MS results show that the change of d-limonene and caryophyllene oxide which is the major component of essential oil of Z. schinifolium Sieb. et Zucc. andβ-Phellandrene Eucalyptol were caused by the exsisting oxygen. The change ofα-Linalool and ionone were caused by microwave radiation.Fourthly, Essential oil of Z. schinifolium Sieb. et Zucc was extracted by vacuum solvent free vacuum microwave extraction (VSFME), and then compared with SFME and HD. The GC-MS results show that VSFME can avoid the occurrence of oxidation reaction and microwave radiation effect, compared with SFME and HD. Therefore, the smell of essential oil was closer to original fragrance of material and was more fresh fragrance. Furthermore, a new conclusion that oxidation reaction and microwave effection are existent and has great influence on the component of the Essential oil. Also, the oxidation reaction of VSFME and HD were not obvious when they were used only. Oxidation reaction and microwave effection were very prominent when VSFME and HD operated at the same time.