Supercritical carbon dioxide extraction of okra (Hibiscus esculentus L) seeds

Pilot-scale supercritical fluid extraction of okra seeds was carried out, using carbon dioxide as solvent, at temperatures of 40, 50 and 60 degrees C and pressures of 150, 300 and 450 bar. Laboratory-scale Soxhlet extraction of the ground seeds was carried out with ethanol and n-hexane. The yields of supercritical fluid extraction and n-hexane Soxhlet extractions were similar. The ethanol Soxhlet extraction gave the highest yield, but the concentrations of beta-sitosterol and tocopherols in this extract were lower than in the supercritical fluid extraction product. The fatty acid profiles of the extracts were determined, and a high unsaturated/saturated ratio was observed. The fatty acid compositions were only slightly different for oils obtained by the different extraction methods. (c) 2005 Society of Chemical Industry.