A procedure is proposed for the supercritical fluid extraction of all-trans-lycopene from tomato using carbon dioxide at 40 degrees C without modifier. The present method minimizes the risk of degradation via isomerization and oxidation of health-promoting ingredients, such as lycopene. The effect of different experimental variables on the solvating power of the supercritical fluid was evaluated in terms of both the selectivity achievable in the process and the yield of the extraction of all-trans-lycopene. Satisfactory separations of the all-trans-lycopene isomers from the cis counterparts were achieved using a C(30) column. The obtained extract contained 88% all-trans-lycopene and 12% cis-lycopene.

Solubilities in supercritical carbon dioxide of the predominant carotenes in tomato skin were measured. The use of a polymeric C 30 RP-HPLC column to analyze the tomato extract made it possible to separate several geometric isomers from each carotene extracted. The Chrastil model was used to assign a solubility equation to each extracted carotene. Different solubility behaviors in supercritical carbon dioxide were shown by carotenes depending on their nature and configuration. The most soluble carotene was all-trans-phytoene and the least soluble was all-trans-lycopene. Significant differences in solubility were observed between the trans and cis isomers of lycopene. The results indicate that a fractionation of the tomato skin carotenes can be achieved by using supercritical CO 2 extraction.Paper no. J10111 in JAOCS 79, 897-902 (September 2002). KEY WORDS:Carotenes, solubility, supercritical carbon dioxide, tomato. EXPERIMENTAL PROCEDURESReagents. Lycopene, 90-95% purity, and α-tocopherol, 99% purity, were obtained from Sigma Chemical (St. Louis, MO); and all-trans-β-carotene, 97% purity, and β-apo-8′-carotenal, 98% purity, were purchased from Fluka Chemical (Buchs, Switzerland). All HPLC-grade solvents, including methanol, dichloromethane, and methyl t-butyl ether (MTBE), were FIG. 2. Carotene contents in the extract obtained using a 313 K extraction vessel temperature and 400 g/L CO 2 density. (A) HPLC chromatogram of phytofluene monitored at 347 nm, and (B) HPLC chromatogram of phytoene peaks at 285 nm. The numbered peaks are tentatively assigned to (1) all-trans-phytofluene; (1') cis-phytofluene; (2) α-tocopherol; (3) all-trans-phytoene; (3') cis-phytoene.

No abstract

The use of supercritical fluid extraction is proposed for obtaining stable extracts with high added value from natural and economical sources. Lipid composition, namely, of FFA, TAG, and FAME, in tomato skin extracts with high lycopene content was determined. Separation of different classes of lipids was achieved from tomato extracts using TLC followed by transesterification and GC, and lycopene and other carotenoids were analyzed by HPLC with a photodiode array detector. In lycopene extracts obtained using supercritical fluids, no FFA were found and polyunsaturated TAG represented only 9.2% of the total TAG content.