Concentration of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) of tuna oil by urea complexation: optimization of process parameters

Production of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) concentrates from tuna oil was optimized. In the process, the liquid recovery yield (Y1) and the total content of DHA and EPA (Y2) were response variables, respectively. A three-factor central composite rotatable design (CCRD) was used to study the effect of urea-to-fatty acid ratio (X1), crystallization temperature (X2) and crystallization time (X3). Second order polynomial regression models for Y1 and Y2 were employed to generate response surfaces. The total DHA and EPA (85.02%) and the liquid recovery yield (25.10%) from tuna oil were obtained at a urea-to-fatty acid ratio of 15 (mole/mole), a crystallization temperature of −5 °C, and a crystallization time of 20 h.