Effect of frozen storage on fatty acid composition and changes in lipid content of Scomberomorus commersoni and Carcharhinus dussumieri

Abstract

Investigated were the changes in fatty acid composition, oxidation and enzymatic deterioration of lipids in frozen (-30°C) fish fillets from the Persian Gulf. The narrow barred Spanish mackerel (Scomberomorus commersoni) and white cheek shark (Carcharhinus dussumieri) were tested with storage times of 0, 1, 2, 3, 4, 5 and 6 months at - 18°C. Statistical results showed that the major fatty acids among the saturated and monounsaturated fatty acids of each fish species were palmitic (C16:0) and oleic (C18:1n-9) acids, respectively. Both linoleic acid (C18:2n-6) and arachidonic acid (AA) (C20:4n-6) were predominant in total n-6 polyunsaturated fatty acids in both mackerel and shark. The EPA (eicosapentaenoic acid; C20:5 n-3) and DHA (docosahexaenoic acid; C22:6 n-3) acids were the major fatty acids among total n-3 acids in both fishes. During frozen storage, the PUFA (40.1 and 23.94%), n-3 (48 and 42.83%), ω6 (41.36 and 50%), PUFA/SFA (56 and 42.23%) and EPA + DHA/C16 (55.55 and 46.66%) contents decreased in S. commersoni and C. dussumieri, respectively. Also peroxide, thiobarbituric acid (TBA) and free fatty acid (FFA) values significantly increased (P < 0.01) with the time of storage. © 2008 Blackwell Verlag, Berlin.