SUPERCRITICAL CO2 EXTRACTION OF BETA-CAROTENE FROM SWEET-POTATOES

Using supercritical CO2 to extract beta-carotene there was approximately a five-fold or a three-fold increase in amount of carotenoids extracted from freeze-dried tissue relative to the amount extracted from oven-dried or fresh tissue, respectively. The most efficient conditions were at 48-degrees-C and 41.4 MPa. Of the total carotenoid content almost-equal-to 20% was inaccessible to supercritical CO2. The HPLC carotenoid profile of sweet potatoes showed that the unextracted tissue contained 90% beta-carotene, primarily as all-trans (ca. 99%). Supercritical CO2 extracts contained up to 94% beta-carotene. The isomer composition of beta-carotene of supercritical extracts showed almost-equal-to 14% 13-cis and 11% 9-cis.