Tea seeds contain many active substances, such as squalene, VE, phytosterols, etc., where the content of squalene in tea seed oil reaches 1% to 2%, but the angle of tea seed oil obtained by conventional refining methods The squalene content is only 30 ~ 40mg / kg.
Because squalene has poor thermal stability, it is easily decomposed or converted into other substances during the oil production process, resulting in a lower squalene content in tea seed oil prepared by conventional refining methods.
Wash the tea seeds to be extracted clean; dry the tea seeds to reduce the water content below 10%, then use a peeler to peel the shells to remove the tea seed shells;
Crush the hulled tea seeds and sieve through a 40-60 mesh sieve;
CO2 supercritical extraction, fluid extraction pressure is 35 M P a, extraction temperature is 40 ° C, CO 2 fluid flow is 700 ~ 800 L / h, extraction time is 3h, crude tea seed oil is obtained;
Freeze centrifugation, place the extracted crude tea seed oil in an environment at 6 ~ 10 ° C and freeze for 20 ~ 30 minutes, and then place the frozen crude tea seed oil in a high-speed refrigerated centrifuge with a speed of 12000 ~ 13000r / min Centrifuge for 10 to 20 minutes to remove impurities, put in a vacuum box at a temperature of 50 to 60 ° C and evacuate for 5 to 7 hours to obtain tea seed oil.
Extraction pressure is the main factor affecting the extraction efficiency of fats and oils. The solubility of fats and oils in CO2 increases with increasing pressure, but the increase in pressure will lead to a substantial increase in equipment investment. In addition, when the operating pressure is high, the color of the extracted fat becomes deeper, which has a certain effect on the quality of the oil.
When the pressure is 35 MPa, the extraction rate of tea seed oil is close to 90%, and the color of the fat is yellow, which meets the standards of edible oil.
The extraction temperature affects the solubility of fats in CO2. At low pressure, an increase in temperature will greatly reduce the density of the fluid, thereby reducing the solubility of the solute.
Under high pressure, the change in fluid density caused by temperature increase is small. At this time, the influence of the saturated vapor pressure of the solute with the increase of temperature plays a leading role, and the solubility of the solute increases. However, the high temperature hinders the diffusion process, squalene is easily decomposed or converted into other substances, and energy consumption is increased.
Extraction time is a parameter that has a lot to do with cost. Under certain conditions, as the extraction time increases, the oil content of the extract gradually decreases. When it is lower than a certain value, extending the extraction time will only increase the cost. It is necessary to choose a suitable extraction time.
Supercritical CO2 extraction of tea seed oil extraction process data from tea seeds:
Pulverization degree: 40 mesh
Extraction pressure: 35 MPa
Extraction temperature: 45°C
Extraction time: 150 min