With the continuous improvement of people’s environmental awareness in recent years and the launch of the national sustainable development strategy, the research and development and adoption of new traditional Chinese medicine extraction and pharmaceutical new processes and technologies have become research hotspots.
New methods that have emerged in recent years include: macroporous resin adsorption and extraction technology, ultrasonic extraction technology, membrane separation technology, and supercritical fluid extraction and separation technology.
Among them, supercritical CO₂ fluid extraction and separation technology is a more eye-catching method. With the increasing maturity of supercritical fluid extraction technology and the deepening of basic research on natural medicines, the application of this technology in traditional Chinese medicine research has attracted much attention and has broad application prospects.
The principle of the supercritical carbon dioxide extraction and separation process is to use supercritical carbon dioxide to have a special dissolving effect on some special natural products. It uses the relationship between the solubility of supercritical carbon dioxide and its density, that is, the influence of pressure and temperature on the solubility of supercritical carbon dioxide. ongoing.
In the supercritical state, supercritical carbon dioxide is brought into contact with the material to be separated, so that components with different polarity, boiling point and molecular weight can be selectively extracted in sequence.
What are the advantages of supercritical CO₂ extraction method compared to steam distillation method?
Supercritical CO₂ fluid extraction is widely used in the extraction of certain chemical components of traditional Chinese medicine, such as volatile oils. There are a large number of literature reports on the research results of supercritical CO₂ extraction compared with steam distillation method for extracting volatile oils from single traditional Chinese medicines.
- Advantage #1: Supercritical CO₂ extraction has a higher extraction rate; a larger amount of volatile oil chemical components can be extracted.
- Advantage #2: Compared with the steam distillation method, the supercritical CO₂ extraction method has a big difference in the types of chemical components.
Seven characteristics of supercritical CO₂ fluid extraction
- Feature #1: Extraction under low temperature conditions. Supercritical CO₂ extraction is performed at a lower temperature (35~40℃) and in a CO₂ gas environment, which can effectively prevent the oxidation and escape of heat-sensitive components, and can better protect the active ingredients of traditional Chinese medicine from being destroyed. Therefore, it is suitable for the extraction of substances that are sensitive to moisture, heat, and light, and components that are easily oxidized, decomposed, and destroyed.
- Feature 2#: The extraction method is clean. CO₂ is an inactive gas, tasteless, odorless, and non-toxic. Therefore, the extract has no residual solvent, and it also prevents poisoning of the human body and environmental pollution during the extraction process. Supercritical CO₂ also has antioxidant and sterilizing effects, which is beneficial to ensuring and improving product quality.
- Feature #3: Strong extraction ability and high extraction rate. Supercritical CO₂ fluid has strong solubility and permeability, fast diffusion rate, and is carried out under continuous flow conditions. The extraction product is continuously removed, and almost all the components to be extracted can be extracted, thus increasing the product yield. and resource utilization.
- Feature #4: The extraction process is simple, time-consuming and high in production efficiency. Supercritical CO₂ extraction combines extraction and separation into one. As soon as the supercritical CO₂ extraction cycle begins, separation also begins. Generally, the components will be separated and separated within 10 minutes of extraction, and the extraction can be completed within 2 to 4 hours. At the same time, it does not require steps such as concentration, and even if an entrainer is added, it can be removed through the separation function.
Feature #5: Selective extraction and separation can be performed. The density, viscosity, solvation capacity, diffusion coefficient and other properties of supercritical CO₂ fluid vary greatly with temperature and pressure. Therefore, it is very sensitive to selective separation. Selective extraction and separation can be achieved by changing the temperature and pressure of the system.
- Feature #6: Can be combined with modern analysis technology. Supercritical CO₂ extraction machine technology can be used in conjunction with modern analytical technologies such as gas chromatography, high performance liquid chromatography, thin layer chromatography, GC/MS, liquid mass spectrometry, etc., so that component analysis can be performed more efficiently and quickly, and objectively Reflects the content of active ingredients in traditional Chinese medicine.
- Feature #7: The slag can be comprehensively utilized. The residue extracted with pure CO₂ can also be well comprehensively utilized to give full play to the comprehensive benefits. For example, corn flour after extracting corn oil, wheat germ after extracting wheat germ oil, and ginger powder after extracting ginger oil can be used as good functional foods or feeds.
Supercritical CO₂ extraction technology is widely used in the extraction of active ingredients of traditional Chinese medicines such as volatile oils, flavonoids, alkaloids, saponins, polysaccharides and quinones. Its application in the extraction and refining of traditional Chinese medicines helps to improve my country’s traditional pharmaceutical products. quality and efficacy. Compared with traditional Chinese medicine production technology, supercritical CO₂ extraction technology has great advantages and market potential.