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

Abstract

Production of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) concentrates from tuna oil was optimized. In the process, the liquid recovery yield ( Y 1) and the total content of DHA and EPA ( Y 2) were response variables, respectively. A three-factor central composite rotatable design (CCRD) was used to study the effect of urea-to-fatty acid ratio ( X 1), crystallization temperature ( X 2) and crystallization time ( X 3). Second order polynomial regression models for Y 1 and Y 2 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.