Storage stability of liver oil from two ray ( Rhinoptera bonasus and Aetobatus narinari) species from the Gulf of Mexico

Abstract

The effect of storage time on the quality of liver oil from two commercial rajiform species ( Rhinoptera bonasus and Aetobatus narinari) captured in the Gulf of Mexico (State of Campeche coast line) was evaluated. Oil characterisation was conducted by physical (specific gravity, saponification index and water content) and chemical analyses (fatty acid content, carotenes and tocopherols) whilst storage stability (peroxide value, free fatty acids, conjugated dienes, anisidine value and changes in docosahexaenoic acid, DHA and content) was studied for 87 days at 25 °C. Increases ( p < 0.05) in free fatty acids, conjugated dienes, peroxide value and anisidine value, and a decrease ( p < 0.05) in DHA were observed during the storage time for both oil species as oxidation proceeded. It was concluded that R. bonasus and A. narinari oils lasted for 52 and 66 days under these storage conditions, respectively.