Recognition of adulteration by other oilsvia direct analysis of the minor components ("sterol fraction") is shown for olive oil. 10 % of various oils were admixed, the free alcohols silylated and the minor components analyzed by on-line coupled LC-GC-FID. For most oils, even smaller additions can be recognized. Admixed oils can no longer be determined, however, if their minor components have been removed by strong raffination. Bleaching of rapeseed oil with 7 % of earth at 180 "C, in fact, completely removed free and esterified sterols.

Citrus medica L. cv. Diamante collected in Calabria (Italy) was extracted by different technologies. The traditional hydrodistillation and solvent methods were compared to the supercritical carbon dioxide extraction (SCF-CO,) performed at two fluid densities: the lowest at 250 g/dm3 and the highest at 875 g/dm3. The effect of the drying process on the peels was studied, and the oil loss was found to be low. The solubility power of CO, (related to its density) was observed. An enrichment of the less-volatile components like sesquiterpenes, heterocyclic compounds and waxes was quantified in the SCF-CO, extracts. The monoterpene hydrocarbons were about 95% in the hydrodistillates and in the pentane extract, but these components decreased in the SCF-extracts to a value lower than 85%. The sesquiterpenes were about 0.62% in the hydrodistillates and 1.40% in the pentane extract, but high quantities were found in the SCF-CO, extracts: 5.64% in the extraction performed at low CO, density and 12.09% at high CO, density. In particular, the SCF-CO, extract was determined to be rich in phytol and citropten. The high content of waxes in SCF-CO, extract at high fluid density is proved by the dilution of the volatile components. Limonene was about 60 g in 100 g of the hydrodistilled, but only 4.5 g was in 100 g of SCF-CO, extract at 875 g/dm3 of CO, density, in the same a decrease of other terpenes was quantified. Differences in the ratio of some monoterpene hydrocarbons were also observed when compared to literature data.

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