title: Comparative analysis of the oil and supercritical CO(2) extract of Cymbopogon citratus Stapf.
abstract: Dried and ground leaves of lemon grass (Cymbopogon citratus Stapf.) were used as a matrix for supercritical extraction of essential oil with CO(2). The objective of this study was to analyze the influence of pressure on the supercritical extraction. A series of experiments were carried out, for 360 min, at 50 degrees C and at different pressures: 90, 100, 110 and 120 bar. Extraction conditions were chosen to maximize citral content in the extract oil. The collected extracts were analysed by GC-MS and their composition was compared with that of the essential oil isolated by hydrodistillation and by steam distillation. At higher solvent density the extract aspect changes passing from a characteristic yellow essential oil to yellowish semi-solid mass because of the extraction of high molecular mass compounds. The optimum conditions for citral extraction were 90 bar and 50 degrees C, at these conditions citral represent more than 68% of the essential oil and the extraction yield was 0.65% while the yield obtained from hydrodistillation was 0.43% with a content of citral of 73%.
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Cagliari, Cittadella Universitaria, 09042 Monserrato, Cagliari, Italy. maronb@unica.it
authors.forename: Bruno
authors.initials: B
authors.lastname: Marongiu
authors.forename: Alessandra
authors.initials: A
authors.lastname: Piras
authors.forename: Silvia
authors.initials: S
authors.lastname: Porcedda
authors.forename: Enrica
authors.initials: E
authors.lastname: Tuveri
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry; D025924:Chromatography, Supercritical Fluid; D031743:Cymbopogon; D006801:Humans; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves; D010938:Plant Oils / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D010938:Plant Oils; D002245:Carbon Dioxide