Production of tocopherol concentrates by supercritical fluid extraction and chromatography

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 a 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 degrees C for soybean flakes and rice 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 soyflakes can be recovered in the SFE step, yielding enrichment factors of 1.83-4.33 for the four tocopherol species found in soy-bean oil. Additional enrichment of tocopherol species can be realized in the SFC stage, ranging from 30.8 for delta-tocopherol to 2.41 for beta-tocopherol.