Comparison of supercritical carbon dioxide and soxhlet extraction of lipids from a brown seaweed, Sargassum hemiphyllum (Turn.) C. Ag.

The fatty acid profiles of Lipids extracted Sargassum hemiphyllum by supercritical carbon dioxide (SC-CO2) were compared with those obtained by Soxhlet solvent extraction using chloroform/methanol. For the pressure range (24.1-37.9 MPa) and temperature interval (40-50 degrees C), 37.9 MPa/ 40 degrees C and 37.9 MPa/50 degrees C gave the highest lipid yield, which was comparable to that of the Soxhlet method, and the highest concentrations of total and individual omega-3 fatty acids, which were significantly higher (p < 0.05) than the solvent extraction. However, SC-CO2 extraction at higher temperature but low-pressure levels (24.1 MPa/50 degrees C) gave significantly lower (p < 0.05) lipid yield and fatty acid concentration than that of lower temperature but of the same pressure (24.1 MPa/40 degrees C). Concentrations of docosapentaenoic acid and docosahexaenoic acid were significantly higher (p < 0.05) at 37.9 MPa/40 degrees C than at 37.9 MPa/50 degrees C. Concentration of the total polyunsaturated fatty acids increased significantly(p < 0.05) and concentration of total saturated fatty acids decreased significantly(p < 0.05) with increasing pressure and solvent density, as indicated by the saturated/ unsaturated fatty acid ratios.