Compared with ordinary solvent extraction, the supercritical CO2 extraction of tea oil has the following characteristics:
(1) It can be extracted at close to room temperature (35-40℃) and under the cover of CO2 gas, effectively preventing the oxidation and escape of heat-sensitive substances. Therefore, most of the nutrients in the tea seeds are retained in the extract, and substances with high boiling point, low volatility and easy pyrolysis can be extracted below their boiling point.
(2) Extracting tea oil with supercritical carbon dioxide is the cleanest extraction method. Since no organic solvent is used in the whole process, there is no residual solvent in the extract. At the same time, the extraction process also prevents the toxicity to the human body and the pollution to the environment. It is a 100% natural processing process.
(3) Extraction and separation are combined into one. When the saturated solute CO2-SCF flows through the separator, the pressure drops, causing CO2 and the extract to quickly become two phases (gas-liquid separation) and separate immediately. Not only is the extraction efficiency high, but it also consumes less energy and saves costs.
(4) CO2 is an inactive gas. There is no chemical reaction during the extraction process. It is a non-flammable gas, tasteless, odorless, and non-toxic, so it is safe.
(5) CO2 is cheap, high in purity, easy to obtain, and can be recycled in the production process, thereby reducing costs.
(6) Both pressure and temperature can be used as parameters to adjust the extraction process. The purpose of extraction is achieved by changing the temperature and pressure. When the pressure is fixed, changing the temperature can separate the substances; conversely, when the temperature is fixed, reducing the pressure can separate the extract. Therefore, the process is simple and easy to master, and the extraction speed is fast.