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 °C), 37.9 MPa/40 °C and 37.9 MPa/50 °C gave the highest lipid yield, which was comparable to that of the Soxhlet method, and the highest concentrations of total and individual ω-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 °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 °C). Concentrations of docosapentaenoic acid and docosahexaenoic acid were significantly higher (p < 0.05) at 37.9 MPa/40 °C than at 37.9 MPa/50 °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. Keywords: Seaweed; supercritical fluid carbon dioxide; omega-3 fatty acids; lipids