highly significantp < 0.01
Under optimal conditions (urea/FA-EE mass ratio of 2.38:1 at 15 °C for 2.5 h of crystallization), the concentrations and recoveries of PUFAs (EPA, DPA, and DHA) were 71.35% and 82.31%, respectively, and the models for EPA, DPA, and DHA were highly significant ( p < 0.01) at the 99% confidence level (EPA purity of 28.97%) [ 98 ].