Extraction of fish oil by fractionation through supercritical carbon dioxide

In the present research, the solubility of fish oil in supercritical carbon dioxide was studied at temperatures of (40, 50, 60, and 70) degrees C and pressures of (13.6, 20.4, and 27.2) MPa. The fractionated fish oil samples collected were then esterified using methanol (with sodium methoxide catalyst). The samples were analyzed by GC to determine the amount of four fatty acid methyl ester (FAME) components extracted, namely, methyl palmitate, methyl oleate, methyl EPA (5,8,11,14,17-eicosapentanoate), and methyl DHA (4,7,10,13,16,19-docosahexenoate). The experimental results showed that the highest solubility of the fish oil (0.921 g of oil/100 g of CO2) was obtained at optimum conditions of 40 degrees C and 27.2 MPa. The solubility of fish oil in supercritical carbon dioxide was found to be higher at lower temperature and at lower fractionation time. Furthermore, the average yield obtained for the combined total of the four FAME components was 66%. Methyl palmitate recorded the highest value of 30.5% at extraction conditions of 50 degrees C and 13.6 MPa. Methyl EPA has the lowest value of 3.24%.