Volatile oil, also known as essential oil, is a general term for a class of oily liquids with aromatic odor. Volatile oil mainly contains terpenoids, aromatic compounds, aliphatic compounds, etc. It is an important active ingredient in herbal medicine with a wide range of biological activities, and is an important raw material for the pharmaceutical, daily chemical, and food industries.
Supercritical CO2 Extraction of Volatile Oil of Ginseng
The supercritical CO2 extraction of essential oil from ginseng was studied by single factor experiment and orthogonal experiment. The effects of extraction pressure, extraction temperature, extraction time, and CO2 flow rate on the yield of volatile oil were investigated, and the optimal process conditions were determined. The yield of ginseng volatile oil (crude oil) obtained is 0.880%, which is much higher than the yield of ginseng volatile oil obtained by the traditional Soxhlet extraction method.
Extraction and chemical composition analysis of volatile oil
When supercritical CO2 extraction technology is used to extract the volatile oil from a single Chinese medicinal material, methods such as gas chromatography-mass spectrometry are often used to study the chemical components of the volatile oil.
Supercritical CO2 extraction of Bibi Lin essential oil
The essential oil of Tibetan medicine Bibilin was extracted with supercritical CO2, and the chemical components of the essential oil were separated and identified by gas chromatography-mass spectrometry.
The results showed that the yield of Bibilin essential oil was 9.7%. A total of 59 chromatographic peaks were separated and 52 components were identified. The main components were piperine (19.24%), bichengene (10.62%), etc., which preliminarily clarified The main material basis of its pungent taste.
Supercritical CO2 extraction of essential oil from Ganzhagari
The essential oil of the Tibetan medicine Ganzhagari was extracted with supercritical CO2, and the chemical components of the essential oil were separated and identified by gas chromatography-mass spectrometry.
The results showed that the yield of Ganzhagari essential oil was 3.08%. A total of 47 chromatographic peaks were separated and 40 components were identified. The main components were tetratetradecane (30.63%), trihexadecane (20.15%), and two Octadecane (16.27%) and so on.
Comparison of Supercritical CO2 Extraction and Steam Distillation
Steam distillation is the most common method for continuous extraction of volatile oil. It has the advantages of simple operation and high efficiency, and is widely used in the production of volatile oil.
In the existing literature, there are a large number of literatures on the supercritical CO2 extraction technology and steam distillation method for the extraction of volatile oil from single Chinese medicinal materials, and compare the extraction rate of volatile oil, the difference in the types and contents of the chemical components of the volatile oil, etc. .
Extract winter flower essential oil
The components of the essential oil extracted from coltsfoot by steam distillation and supercritical CO2 were compared.
The results showed that the yield of essential oil by steam distillation was 0.13%, and the product was a pale yellow oily liquid, which could be completely dissolved in ethanol and dichloromethane, and its aroma was mainly sweet and floral, with a slight cooking smell;
The yield of supercritical CO2 extraction of essential oil reaches more than 1%. It is a paste-like substance, and its aroma is mainly sweet, floral and delicate, with a slight waxy aroma.
The essential oil extracted by supercritical CO2 can be completely dissolved in dichloromethane. When the solvent is absolute ethanol, some of the white powder cannot be completely dissolved.
Gas chromatography-mass spectrometry
The results of gas chromatography-mass spectrometry showed that the main components of essential oils obtained by steam distillation were β-bisabolene (16.83%), carrisene oxide (12.13%), and octadecatriene (6.45%). , Undecene (6.30%) and Cycloundecene (4.53%), etc.;
The essential oil extracted by supercritical CO2 contains coltsfoot (13.94%), carrisene oxide (11.97%), β-bisabolene (4.37%), octadecatriene (4.19%) and gold. Setoside (3.40%) and so on.
Comparison of two extraction methods
Comparison of the chemical components contained in essential oils obtained by two different preparation methods. The chemical components contained in essential oils by steam distillation are mostly volatile substances with smaller molecular masses. In addition to volatile substances in supercritical CO2 extraction, essential oils also contain volatile substances. Contains some of the higher molecular weight components in coltsfoot;
Small molecule characteristic substances, such as β-bisabolene, spartol, carnitrene oxide, etc., occupy a large proportion in the two essential oils, but the content in the essential oil extracted by steam distillation is higher;
Part of the characteristic substances of coltsfoot with larger molecular mass, such as coltsfoot ketone and coltsfoot glycol, are only contained in supercritical CO2 extraction essential oils.
It can be seen that in the process of extracting coltsfoot essential oil, steam distillation is more focused on the volatile components of small molecular weight, while the supercritical CO2 extraction technology not only extracts some small molecular weight compounds, but also the chemical components of medium molecular weight. It also has a certain extraction effect, which is why the yield of supercritical CO2 extraction of essential oils is higher than that of steam distillation essential oils.
In addition, the supercritical CO2 extraction essential oil also contains more higher alkanes, so it cannot be completely dissolved in anhydrous ethanol.
In the comparative study of supercritical CO2 extraction technology and steam distillation method for the extraction of volatile oil, the extraction rate of volatile oil by supercritical CO2 extraction technology is generally higher than that of steam distillation;
In terms of the quantity of volatile oil chemical components, supercritical CO2 extraction technology is more than steam distillation, and the types of chemical components are also quite different.
Ganzhagari (Rubus amabilis Focke)
The berry (scientific name: Rubus amabilis Focke) is a plant of the genus Rosaceae and Rubus.
Shrubs, 1-3 meters high;
Branches purple-brown or dark brown, glabrous, with sparse prickles;
Flowering branches are short, pilose and small prickles.
The lobules are 7-11, ovoid or ovate-lanceolate, 1-5.5 cm long and 0.8-2.5 cm wide. The small leaves usually located on the upper part of the leaf shaft are larger than the lower ones.
Flowers solitary at the top of lateral branchlets, drooping; pedicel 2.5-6 cm long, pilose, sparsely small prickles, sometimes with sparse glandular hairs;
Flower diameter 3-4 cm;
Calyx greenish reddish, densely pubescent outside;
Sepals broadly ovate, 1-1.5 cm long, apex acuminate or protruding;
The petals are nearly round, white, slightly longer or equal to the sepals;
Filament linear, slightly wider at base, whitish; style light green, glabrous.
The fruit is oblong and sparsely oval, 1.5-2.5 cm long, 1-1.2 cm in diameter, red, sparsely pubescent when young, and glabrous when old, edible;
Nuclear kidney shape, slightly reticulated.
Flowering period from April to May, fruit period from July to August.