Enrichment of EPA and DHA from sardine by supercritical fluid extraction without organic modifier: I. Optimization of extraction conditions

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play an important role in the prevention of a lot of human diseases, and the supplementation in the alimentation of such fatty acids is thus recommended in certain diets. EPA and DHA were obtained by extraction and fractionation of fish industries waste, such as fish heads, produced for fish canning. Supercritical fluid extraction (SFE) of sardine oil was performed to optimize various parameters, such as pressure, temperature, CO2 rate and time in order to obtain the highest yield of extracted oil with the highest amount of EPA and DHA in the extraction product.An experimental design was planned and the experiments were performed with a supercritical pilot (Hewlett-Packard), while the composition of each extract was determined by GLC.In the first approach, the oil yield was determined. Then, a quadratic model with three variables was studied to maximize the EPA and the DHA concentrations. A multicriteria optimization, using the desirability function, was performed to determine the best level for each parameter. Pressure, temperature and CO2 rate were, respectively, set at 300 bars, 75 °C and 2.5 ml/min during 45 min extraction. A yield of 10.36% of extracted oil (compared with the dry material) was achieved with an amount of 10.95% of EPA and 13.01% of DHA (compared with all fatty acids of the extract). This result was compared with a traditional solvent extraction and the solvent extraction yield seemed to be better. In fact, the advantages of SFE were a shorter extraction time, a prevention of heating and a better organoleptic aspect by excluding the use of legally not allowed organic solvents.