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Research on the Microwave-assisted Extraction of Essential Oil in Traditional Chinese Medicine and Analysis for the Change of Chemical Composition

Author: TaoJinZhuan
Tutor: ZouXiaoBing
School: Chongqing University
Course: Chemistry
Keywords: Solvent-free microwave assisted extraction Microwave steam distillation. Steam distillation. Volatile oil
CLC: TQ461
Type: Master's thesis
Year: 2010
Downloads: 200
Quote: 0
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Abstract

Microwave assisted extraction Essential Oils use within the heating characteristics of the microwave, with a fast, efficient. However microwave is an electromagnetic wave, whether it will cause the volatile oil composition changes in the heat extraction process. To solve this problem, the paper, the choice of star anise, pepper, mint, ginger, mugwort, Agastache Chinese medicine as the research object, using a solvent-free microwave assisted extraction and microwave steam distillation to extract the volatile oil study solvent-free microwave-assisted extraction and microwave extraction steam distillation mechanism; examine differences in the relative content of the chemical composition of the volatile oil extraction process of influencing factors; explore microwave the impact of changes in the volatile oil components. The contents of this paper are as follows: solvent-free microwave assisted extraction volatile oil cells as intracellular vapor is distilled; Microwave steam distillation, the water molecules to the cells within the volatile oil extracted aqueous phase become free of volatile oil and further steam distillation. Star anise, or flake mint leaves, does not exist inside and outside the two glands in the form easier to be extracted, the extraction rate of two microwave-assisted extraction is less; while pepper existence of both internal and external glands and the epidermis The volatile oil is easier to extract, the deep volatile oil and subject to certain diffusion process reaches the epidermis before they can be extracted, so the extraction rate of the two types of microwave-assisted extraction varied. ② The volatile oil of different extraction methods for chemical composition analysis by gas chromatography - mass spectrometry and compared with steam distillation, the results show that: in the process of extraction of star anise, solvent-free microwave-assisted extraction and microwave steam distillation easy to obtain a relatively low boiling point, low molecular weight compounds; extract Volatile Oil process, solvent-free microwave-assisted extraction method in the same microwave power, with the increase in extraction time, trans-4 - isopropyl-1 - A -2 - cyclohexyl alcohol, cis-4 - isopropyl-1 - methyl-2 - cyclohexyl enol, eucalyptus oil pigment, trans-3 - cis-3 terpenols - terpenols and such as to reduce the relative content of the five compounds has increased, while the content of α-linalool. Show that a longer extraction time, eucalyptus oil pigment compounds in the proton catalyzed rearrangement is converted into α-pinacol. The volatile oil extracted by the steam distillation method to microwave radiation and analyze their results, microwave radiation through the volatile oil of eucalyptus oil prime a reduced content of an α-linalool content increased, and the role of the microwave to promote the rearrangement reaction of occur. Solvent-free microwave-assisted extraction process of volatile oil extracted mint pulegone up the least amount of menthol; Conversely, steam distillation pulegone least amount of menthol; while between microwave steam distillation between the two; less moisture extraction system solvent-free microwave assisted extraction of volatile oil oxidation reaction occurs in contact with oxygen and converted into other compounds. Mint leaves volatile oil of the steam distillation from the microwave radiation and analyze the results. Menthone, iso-menthone, and menthol relative content decreased, while the of pulegone and menthofuran one relative content increased, and the content of pulegone nearly solvent-free microwave assisted extraction. That microwave the via Isomenthone menthol, mint ketone to the pulegone the oxidation there is a significant role. In the extract of ginger essential oil, solvent-free microwave assisted extraction more β-phellandrene. The solvent-free microwave assisted extraction extraction system less moisture than the microwave steam distillation can also get more lipophilic hydrocarbon monoterpenes compounds.

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