Supercritical Carbon Dioxide Extraction of PUFA Rich Oil from Freeze Dried Tuna Red Meat

Supercritical fluid extraction (SFE) is an emerging technology for extraction and isolation of valuable compounds from natural products. Supercritical carbon dioxide (SCO2) is one of the most commonly used solvents in SFE and has gained importance as a "green" or environment friendly solvent. In this study, polyunsaturated fatty acid (PUFA) rich oil from freeze dried yellowfin tuna (Thunnus albacares) red meat was extracted using supercritical carbon dioxide. Red meat, a by-product obtained from tuna processing forms about 9-11% of the total body weight of tuna. Lipid extraction from freeze dried tuna meat was performed at a temperature of 60 degrees C and pressure of 35 MPa for 3 h. The flow rate of CO2 was kept constant at 175 l h(-1). The extracted oil was collected in two separators both held at 5 MPa pressure and temperature of 50 degrees C and 40 degrees C respectively. The antioxidant tocopherol (0.5%) was added to the extracted oil and stored at 2-4 degrees C for further analysis. The yield of oil obtained was 5% and it was found to be rich in polyunsaturated fatty acids like docosahexaenoic, eicosapentaenoic and arachidonic acid constituting 31, 5 and 4% of the total fatty acids respectively. Palmitic and stearic acid were the most abundant saturated fatty acids present constituting 23 and 15% of total fatty acids respectively. Oleic acid contributed 18% of the total fatty acids. SFE was effective in extraction of fatty acids from tuna red meat with minimal losses.