Application of supercritical fluid extraction in various industries

Application of supercritical fluid extraction in various industries

Supercritical fluid extraction technology is a new kind of biological separation and refining technology, which has been developing rapidly in recent years.

In particular, since the world's first symposium on "supercritical gas extraction" was held in Essen, west Germany in 1978, it has been widely used in the fields of chemistry, petroleum, food, medicine and health care products. The application of supercritical fluid extraction is briefly introduced.

(1) application in food

The traditional method of edible oil extraction is ethane extraction, but the amount of solvent in edible oil produced by this method cannot meet the requirements of food management law. In the United States, soybean oil extraction by supercritical carbon dioxide extraction (SCFE) was successful, the product quality was greatly improved, and there was no pollution problem. At present, supercritical carbon dioxide can be used to extract oil from sunflower seeds, red flower seeds, peanuts, wheat germ, palm, and cocoa beans. This method has higher recovery than traditional press method, and there is no solvent separation problem. Experts believe this method can revolutionize the process of oil extraction.

The caffeine in coffee, which is harmful when consumed in large quantities, must be removed from the coffee. The traditional industrial method is to use dichloroethane to extract, but dichloroethane not only extracts caffeine, but also extracts the aromatic substances in coffee, and the remaining dichloroethane is not easy to remove, affecting the quality of coffee. Dr Zesst, of the Max plank coal institute in west Germany, developed a special technique for extracting caffeine from coffee beans using supercritical carbon dioxide. The biggest advantage of this technology is that it replaces the trace halogenated hydrocarbon solvent which still remains harmful to human body in the product, the content of caffeine can be reduced from about 1% to 0.02%, and the good selectivity of CO2 can retain the aromatic substance in coffee.

ADL, an American company, recently developed a method of extracting alcohol with SCFE technology, and has patented a technique for removing excessive oil from greasy fast food without losing its original color, smell, appearance and internal structure.

(2-1). Application in medicine and health care products

Professor Stahl of Saarland university in west Germany has achieved satisfactory separation of many medicinal plants using the SCFE method for their active ingredients (such as various alkaloids, aromatic and oily components).

In the production of antibiotic drugs, traditional methods often use organic solvents such as acetone and methanol, but it is very difficult to remove the solvent completely without deterioration of the drug. If the SCFE rule is adopted, it can completely meet the requirements. ADL has extracted the active ingredients for the treatment of cancer from seven plants, making it a real clinical application.

Many researchers believe that fish oil and omega-3 fatty acids are good for your health. These lipids can also be obtained from phytoplankton. Lipids obtained in this way do not contain cholesterol. J.K.P. olak et al. successfully extracted lipids from algae, and chlorophyll is not extracted from supercritical CO2, thus eliminating the bleaching process of traditional solvent extraction.

In addition, ginkgo flavonoids extracted from ginkgo leaves by SCFE method, polyene unsaturated fatty acids (DHA, EPA) extracted from fish entrails and bones, sea buckthorn oil extracted from sea buckthorn seeds, and lecithin extracted from yolk have unique curative effect on cardiovascular and cerebrovascular diseases. Japanese scholar miyamoto et al. extracted the active ingredients from medicinal plant osmanthus l., white mulberry, liquorice root, lithospermum, safflower, and evening primrose.

(2-2). Application of Chinese herbal medicine active ingredients extraction

1. The industrialization situation of traditional Chinese medicine and the significance of applying new technology

Traditional Chinese medicine (TCM) has a long history in China. As the toxic and side effects of chemical drugs are gradually recognized by people and the synthesis of a new drug requires huge investment, western medicine and western medicine are far from meeting the clinical needs for the treatment of common diseases and difficult diseases that threaten human health. In the face of the rapid development of science and technology, especially the pharmaceutical industry, the increasingly frequent international medical academic exchange activities and the increasingly fierce competition in the pharmaceutical market, it has become the consensus of TCM workers to realize the modernization of traditional Chinese medicine and to be in line with international practices. After the reform and opening up to the 15th national congress of the CPC, China has made clear the strategic direction and thought of the development of traditional Chinese medicine, and put forward the strategic subject goal of "scientific and educational development". The development of traditional Chinese medicine has made a great step forward. In traditional Chinese medicine production VAT of boiling, steaming cauldron boil and plaque, spoon, cylinder has improved the condition of production equipment, and a multi-purpose extraction tank, stainless steel outer circulation evaporation, multiple effect evaporator, fluidized dryer and other equipment, proprietary Chinese medicine formulations have larger development, by the pill, powder, plaster, Dan agent mainly developed into granules, tablet, capsule, oral liquid, a small amount of booster injection dosage forms, etc. The value of the production of traditional Chinese medicine has quintupled since 1979, accounting for more than 30 percent of the value of the pharmaceutical industry. However, it is difficult for Chinese patent medicine to be registered, sold and used in foreign countries. In terms of the trade volume of natural medicines in the world, China accounts for only about 1%, which is not in line with the status of a major producer of natural medicines. The reason is that the level of modern engineering technology is not high, and the modernization of preparation technology and dosage form is still very backward. The lack of scientific and strict process operating parameters in many aspects of the production process not only leads to high consumption and low efficiency, but also leads to effective component loss, unstable curative effect, inconvenient use of large doses, poor product appearance and color, and unstable internal quality. At the same time, there is a lack of systematic quantitative indicators, and most products lack internal quality standards with basically consistent curative effect. Many complex formulations also struggle to understand the physical basis of their effects.

The situation of "pill, powder, cream, Dan, immortals difficult to distinguish" has not been fundamentally changed. To change this situation, the western medical community should accept traditional Chinese medicine and enhance its competitive position in the international market. The emphasis of the modernization of traditional Chinese medicine products can be simply described in eight words, namely "effective, small amount, safe and controllable". In fact, it covers a wide range, and the problems to be solved are relatively complicated. However, the first and most critical problem is to extract separation technology, modernize preparation technology, and standardize and standardize quality control. For this reason, many medical experts have proposed to adopt advanced technologies such as supercritical fluid technology, membrane separation technology, freeze-drying technology, microwave radiation-induced extraction technology, slow controlled release preparation technology, various kinds of advanced chromatographic and spectral analysis, etc. for the research and development and industrialization of traditional Chinese medicine.

At the end of March 1998, more than 60 experts and scholars from more than 20 units in China and Hong Kong gathered in xiamen university to discuss the modernization of traditional Chinese medicine, especially the major scientific basis issues in the complex system of traditional Chinese medicine. Supercritical fluid technology was also proposed. The us EPA has gradually adopted supercritical fluid extraction as the standard alternative to solvent extraction. However, supercritical fluid technology is only one of many advanced technologies that can be used in the modernization of traditional Chinese medicine.

2. Advantages of supercritical fluid extraction in the modernization of traditional Chinese medicine

In SCF technology of supercritical fluid, SFE extraction technology is closely related to the modernization of traditional Chinese medicine, and CO2 is the most commonly used supercritical fluid. Compared with traditional Chinese medicine, the supercritical CO2 extraction technique has many unique advantages:

2.1 strong extraction capability and high extraction rate. The effective components of traditional Chinese medicine were extracted with supercritical CO2. Under the optimal process conditions, the extracted components could be extracted almost completely, thus greatly improving the product yield and resource utilization. At the same time, with the continuous progress of supercritical CO2 extraction technology, the application of perfluoropolyether ammonium carbonate (PEPE) extended supercritical CO2 extraction to water solution system, making it possible to extract supercritical CO2 extraction of strong polar compounds such as proteins.

2.2 the extraction capacity depends on the density of the fluid, and ultimately depends on the temperature and pressure. Changing one of them or changing at the same time can change the solubility. The separation of various substances in traditional Chinese medicine can be selectively conducted, so as to reduce impurities and make the effective components of traditional Chinese medicine highly enriched. It is convenient to reduce dosage and quality control, and the appearance of the product is greatly improved.

2.3 the critical temperature of supercritical CO2 is low and the operating temperature is low, which can keep the effective components of traditional Chinese medicine intact without damage or sub-biochemistry. Therefore, it is especially suitable for the extraction of ingredients with strong thermal sensitivity and easy oxidative decomposition and destruction.

2.4 fast extraction time and short production cycle. As soon as the supercritical CO2 extraction (dynamic) cycle begins, the separation begins. Generally, the extraction can be separated and separated within 10 minutes, and the extraction can be completed within 2 to 4 hours. At the same time, it does not require such steps as concentration, even if the entrainer is added, it can be removed by the separation function or simply concentrate.

2.5 supercritical CO2 extraction, operating parameters are easy to control, therefore, effective components and product quality are stable.

2.6 supercritical CO2 can also directly extract different parts from single or compound Chinese medicine or extract extracts directly for pharmacological screening and development of new drugs, greatly improving the speed of new drug screening. At the same time, it can extract many substances not mentioned by traditional methods, and it is easier to find new ingredients from traditional Chinese medicine, so as to discover new pharmacological properties and develop new drugs.

2.7 supercritical CO2 also has antioxidant and sterilization effects, which is conducive to guarantee and improve product quality.

2.8 supercritical fluid extraction has been applied in analysis or in combination with GC, IR, MS, LC, etc., and has become a highly efficient analytical method. It can be used in the quality analysis of traditional Chinese medicine to objectively reflect the true content of the active ingredients in traditional Chinese medicine.

2.9 with pharmacological and clinical evidences, the extraction of traditional Chinese medicine by supercritical CO2 is not only superior in process, stable in quality and easy to control in standard, but its pharmacological and clinical effects can be guaranteed or better.

2.10 supercritical CO2 extraction process is simple, easy to operate, labor saving and large amount of organic solvent, and reducing waste pollution, which undoubtedly provides a new method of extraction, separation, preparation and concentration for the modernization of traditional Chinese medicine.

In addition, the reiss process and GAS process in supercritical fluid crystallization technology can produce ultra-fine particles with uniform size, which can be used to prepare controlled release pellets and other dosage forms, which can be used to prepare new Chinese medicine dosage forms.

3. Application and prospect of supercritical fluid technology in TCM modernization

In the supercritical fluid technology, is a research and development is widely applied technology of supercritical fluid extraction, the extraction and separation of the SFE technique is a new kind of technology, due to its own characteristics, both at home and abroad has widely used in food, spices, and other fields, and in the field of traditional Chinese medicine (TCM), foreign or domestic most unit engaged in SFE technology research and development applications are reported, but the lack of systematic, mostly stay in the middle of the Chinese medicine effective component or raw material extraction, this is just one aspect of the used in traditional Chinese medicine (TCM). The research and development of traditional Chinese medicine has its particularity, that is, it must have pharmacological clinical effects. Therefore, SFE technology used in traditional Chinese medicine must be combined with pharmacological clinical research. The viability or potential of SFE technology in this field can be truly realized only when the technology is superior and the pharmacological clinical effect is guaranteed or better.

(3). Extraction of natural flavors and spices

By SCFE method not only can effectively extract the aromatic constituents extraction spices, but also can improve the product purity, can maintain its natural fragrance, such as from osmanthus, jasmine, chrysanthemum, plum, orchid, rose extract essence, extracted from pepper, cinnamon, mint, spices from celery seed, ginger, guan with weeds seeds, fennel, amomum fruit, anise, cumin, such as raw material to extract the essential oil, not only can be used as a spice, and some of the essential oil also has high medicinal value.