Supercritical carbon dioxide extraction of cuphea seed oil.

摘要

Cuphea seed oil (CSO) is a potential domestic source of medium chain fatty acids. Although CSO has been obtained using solvent extraction and screw pressing, both methods suffer from disadvantages. Supercritical carbon dioxide (SC-CO₂) extraction is a promising alternative extraction technology. It is a very effective means to extract vegetable oils, non-toxic, non-flammable, easy to separate from extracts (i.e., no solvent residues) and there are no solvent disposal costs. This research compared SC-CO₂ and soxtec petroleum ether for the extraction of CSO. The CSO yield for the petroleum ether was 29.7% while the SC-CO₂ was 28.1%. The free fatty acid content for the SC-CO₂ extract was only 8.8% while the petroleum ether extract was 15.0%. The acid values were also much higher for the petroleum ether extract (i.e., 29.8) than for the SC-CO₂ extract (i.e., 17.4). The Gardner color of the SC-CO₂ extract was determined to be 2+ while the color of the petroleum ether soxtec extract could not be determined because it was very dark due to the presence of chlorophyll. Although the two extraction methods differed slightly in their individual fatty acid compositions, the magnitudes of the differences were inconsequential. This research demonstrated that CSO can be effectively extracted using SC-CO₂ at a relatively low temperature and pressure (i.e., 50 degrees C and 20.7 MPa) to give a very high quality oil. Cuphea seed oil's status as a specialty oil and its corresponding higher value make its extraction using SC-CO₂ an economically viable option.