Comparative analysis of the oil and supercritical CO2 extract of Elettaria cardamomum (L.) maton

The volatile oil of Elettaria cardamomum (L.) Maton seeds was obtained by supercritical CO2 extraction (SC-CO2). The effect of the extraction conditions on the yield and composition of the resulting cardamom volatile oil was examined by testing two pressure values, 9.0 and 11.0 MPa; two temperatures, 40 and 50 degreesC; two flow rate values, 0.6 and 1.2 kg/h; and two particles size values, 250-425 and >850 mum. The extraction conditions that gave the highest yield, Y (grams of extract per gram of seeds), of 5.5%, were as follows: pressure, 9.0 MPa; temperature, 40 degreesC; carbon dioxide flow, phi = 1.2 kg/h; and particles sizes in the range of 250-425 mum. Waxes, recovered as traces, were entrapped in the first separator set at 9.0 MPa and -10 degreesC. The oil was recovered in the second separator working at 1.5 MPa and 10 degreesC. The main components were as follows: alpha-terpinyl acetate, 42.3%; 1,8-cineole, 21.4%; linalyl acetate, 8.2%; limonene, 5.6%; and linalool, 5.4%. A comparison with the hydrodistilled oil, obtained at a yield of 5.0%, did not reveal any consistent difference. In contrast, the extract obtained using hexane, Y = 7.6%, showed strong composition differences. Indeed, the volatile fraction of the extract was made up mainly of the following: limonene, 36.4%; 1,8-cineole, 23.5%; terpinolene, 8.6%; and myrcene, 6.6%.