Ofessential Oil Research Articles

Critical review of supercritical carbon dioxide extraction of selected oil seeds

Supercritical carbon dioxide extraction, as a relatively new separation technique, can be used as a very efficient process in the production of essential oils and oleoresins from many of plant materials. The extracts from these materials are a good basis for the new pharmaceutical products and ingredients in the functional foods. This paper deals with supercritical carbon dioxide extraction of selected oil seeds which are of little interest in classical extraction in the food industry. In this article the process parameters in the supercritical carbon dioxide extraction, such as pressure, temperature, solvent flow rate, diameter of gound materials, and moisture of oil seed were presented for the following seeds: almond fruits, borage seed, corn germ, grape seed, evening primrose, hazelnut, linseed, pumpkin seed, walnut, and wheat germ. The values of investigated parameters in supercritical extraction were: pressure from 100 to 600 bar, temperature from 10 to 70oC, diameter of grinding material from 0.16 to 2.0 mm, solvent flow used from 0.06 to 30.0 kg/h, amount of oil in the feed from 10.0 to 74.0%, and moisture of oil seed from 1.1 to 7.5%. The yield and quality of the extracts of all the oil seeds as well as the possibility of their application in the pharmaceutical and food, industries were analyzed.

An approach to the static–dynamic subcritical water extraction of laurel essential oil: comparison with conventional techniques

The coupling of a subcritical extractor with a three-way inlet valve and an on/off outlet valve was used for performing static–dynamic subcritical water extractions for the isolation of essential oils. The applicability of the assembly was tested using laurel leaves as a model sample, but can be extended to other natural products. The compounds were removed from the aqueous extract by a single extraction with 5 ml of hexane, individually separated and detected by gas chromatography–flame ionisation detection and identified by electron ionization mass spectrometry. The proposed method was compared with both conventional (hydrodistillation and dichloromethane manual extraction) and recent (subcritical dichloromethane extraction) alternatives in terms of rapidity, efficiency, cleanliness, possibility of manipulating the composition of the oil and quality of the oil, revealing the proposed method to be clearly advantageous. This fact, together with the good precision for the overall method [(RSD <15% for n = 6) for each compound], make it a good alternative to both conventional and recent counterparts.

Terpenoid chemistry. XX. Myoporone and dehydromyoporone, toxic furanoid ketones from Myoporum and Eremophila species

Certain samples of essential oils from Myoporum deserti, M. betcheanum, M. acuminatum, Eremophila maculata, and E. latrobei have been shown to contain myoporone and/or 10,ll-dehydromyoporone. The ambiguity regarding the stereochemistry of myoporone (previously known from M, bontioides) has been resolved,(-)-myoporone being shown to possess the S configuration by degradation to (S)-(+)-2-methylglutaric acid. (-)-Dehydromyoporone, m.p. 32.5-33.5, [x]D ? 15�, has the S configuration as shown by degradation to (S)-(-)-3-methyladipic acid and hydrogenation to (S)-(-)-myoporone, m.p. 17.5-19�, [x]D-5.3�. Both ketones activate the typical ngaione pathology on intraperitoneal injection into mice but myoporone is not toxic to sheep. Myoporone from Myoporum species shows wide variations in optical purity.