Submitted to: Separation Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/1993
Publication Date: N/A
Citation: Interpretive Summary: Vegetable oils can be extracted using highly compressed gases called supercritical fluids. This removal of oils from seeds using supercritical fluids can be achieved quite quickly and efficiently using very high pressures and moderate temperatures. Vegetable oils also contain minor components/chemicals which have value in both edible and non-edible applications. For example, soybean oils contain a chemical called tocopherol which has high value and many applications in the food and polymer industries. In this study, tocopherols have been partially separated initially from their corresponding seed oil matrix using moderately pressurized carbon dioxide. In this extraction step, a concentrated tocopherol sample is obtained for further purification. Samples obtained in this initial extraction step are further subjected to another enrichment process called chromatography in which tocopherols are further separated and concentrated. A product is then obtained having tocopherols concentrated in a small amount of vegetable oil that can be used in commercial applications. The prime advantage of the supercritical fluid-based process is its environmental compatibility along with its ability to remove these high value components while not effecting the seed oil matrix.
Technical Abstract: Supercritical fluid extraction (SFE) has been combined with supercritical fluid chromatography (SFC) in a preparative mode to develop a system for fractionating and enriching high value constituents contained in seed oil matrices. The system consists of an extraction step sequenced on-line with a sorbent filled column, which permits an SFE-enriched tocopherol fraction to be diverted onto the chromatographic column, for further enrichment of the tocopherols. For the SFE stage, the tocopherol enrichment was optimized at 25 MPa and 80 deg C for soybean flakes and rich bran; however, total tocopherol recovery and enrichment was also found to be a critical function of the mass ratio of CO2/seed charge. Approximately 60% of the available tocopherols in soya flakes can be recovered in the SFE step, yielding enrichment factors of 1.83-4.33 for the four tocopherol species found in soybean oil. Additional enrichment of tocopherol isomers can be realized in the SFC stage; ranging from 30.8 for delta tocoherol to 2.41 for beta-tocopherol.