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.

No abstract

Enantiomeric compositions of chiral terpenes in commercial fruit beverages were examined by solid phase microextraction-gas chromatography (SPME-GC). Optimization of the method was accomplished on the basis of some parameters involved in the extraction, such as heating temperature and extraction time, that provided the highest peak areas, 60 degrees C and 2 min being the optimal values. With the proposed method relative standard deviation (RSD) values from three replicates ranging from 2 to 12% were obtained. The enantiomeric distribution of some terpenes remained constant, whereas other terpenes (linalool, terpinen-4-ol, and alpha-terpineol) exhibited a considerable variation among samples. This can be indicative of the eventual addition of aromas to some fruit beverages.

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.

Chiral terpenes in nonprocessed orange juices of different geographical origins were examined by two different approaches: steam distillation–solvent extraction–gas chromatography–mass spectrometry (SDE-GC-MS) and solid-phase microextraction–gas chromatography(SPME-GC). The two sample preparation techniques were compared with regard to their effectiveness in determining the enantiomeric distributions of chiral compounds. Most target compounds exhibited constant enantiomeric ratios in all juices when either of the two approaches was used. Exceptions were found for terpinen-4-ol and β-citronellol, whose of enantiomeric purity ratios varied significantly according to the geographical origin of the sample. These results may aid in guaranteeing the authenticity and thus the quality and safety of orange juice. A comparison between the two extraction procedures revealed SPME to be more reliable for stereochemical studies, since harsh experimental conditions that can bring about racemization are not required in such studies.