SUPERCRITICAL CO₂ EXTRACTION
Supercritical fluid extraction (SFE) is a kind of separation method to extract necessary components (or harmful components) from liquid or solid by using supercritical fluid extractant. Supercritical fluid (SCF) refers to the fluid whose temperature and pressure exceed the critical temperature and pressure. SCF has the characteristics of gas-liquid two-phase; It not only has a good ability to dissolve many liquid-solid substances, but also has a high diffusion coefficient and low viscosity equivalent to that of gas. It is easy to separate from the extracted liquid-solid substances.
This solubility of the fluid is very sensitive to the small changes of the system pressure and temperature, so the solubility of various components can be adjusted by changing the system temperature and pressure. Its separation operation effect is much superior to the general separation technology, and can achieve the purpose of extracting the required substances with high purity.
SCF is especially commonly used for CO₂ ; CO₂ has a critical pressure of 739kpa and a critical temperature of 31.1 ℃. It is non-toxic, non side effect, non combustible, inexpensive, non polluting to the environment, and has excellent dissolution of many natural product components. It is the best supercritical fluid. Because the temperature of CO₂ supercritical extraction process is far lower than that of other existing extraction technologies, SFE technology has great application advantages in natural flavor extraction.
Advantages of Supercritical CO₂ Extraction
Prevent oxidation and decomposition of heat sensitive active substances
SFE CO₂ is a clean and green extraction method
The product conforms to the concept of green and health
High extraction efficiency, low energy consumption and cost saving
CO₂ is recyclable and environmentally friendly
No harmful discharge, environmental protection
APPLICATION OF SFE-CO₂
Numerous advantages based on supercritical CO₂ fluid extraction
SFE CO₂ technology is more and more widely used in the extraction and separation of natural spices and essential oils.
Different parts of natural plants have their own characteristics in chemical composition. Generally, flowers, fruits, roots and rhizomes contain aromatic volatile oil; The stems, skins, leaves and other parts contain higher pigments and pectins, and less volatile components; The contents of higher fatty acids and oils in fruits and seeds were relatively high. When supercriticalCO₂ fluid extraction technology is used to extract plants, the extraction of roots, rhizomes, stems, skins and fruits is generally easier to operate and has more application potential.
Properties of Supercritical CO₂ Fluid
Supercritical CO₂ fluid is lipophilic and has good solubility for aromatic substances, essential oils and other low polar substances. The whole extraction and separation process is carried out under low temperature and high pressure, without chemical reaction and solvent residue, and the original flavor, color and activity of components are retained to the greatest extent. The whole process is actually a physical gas-liquid separation process, especially suitable for the separation and purification of unstable natural products and physiologically active substances, In line with the international trend of natural health. SFE CO₂ has become one of the most effective processes for obtaining high-quality natural extracts and essential oils. In particular, the application in natural flavor and essential oil has become the most successful field in the industrialization of SFE CO₂ technology.
