Abstract

A simple and relatively inexpensive procedure to obtain 90% eicosapentaenoic acid + docosahexaenoic acid concentrates from sardine oil involved a two-step winterization of the oil (10 and 4°C), followed by saponification and selective precipitation of saturated and less unsaturated free fatty acids by an ethanolic solution of urea. Antioxidant effects of butylated hydroxytoluene, dl-?-tocopherol, and two natural antioxidants, quercetin and boldine, added to the concentrate (0.5% wt/vol), were compared in the Rancimat at 60°C. dl-?-Tocopherol was unable to inhibit concentrate oxidation. Butylated hydroxyanisole and butylated hydroxytoluene had induction periods of 1.7-1.8 h compared to the control (1.0 h). A mixture of quercetin + boldine (2:1 w/w) significantly increased the induction period to 4.5 h.