The effect of processing, frozen storage, and packaging on the iron content of mackerel, white hake, and cod

The increasing popularity of seafood because of its health benefits, can lead to a gradual substitution of fish for red meats (one of the best sources of iron) in the American diet. This study was designed to determine the effect of processing, packaging, and frozen storage on the iron content of select lean and fatty fish species.; Cod and white hake were used as the lean species and mackerel as the fatty species. Total, heme, and nonheme iron were determined. Fillets, fillet minces with and without skin, headed and gutted (H&G) fish mince, and frame mince were studied. Samples were stored at {dollar}-{dollar}7{dollar}spcirc{dollar}C, {dollar}-{dollar}14{dollar}spcirc{dollar}C, {dollar}-{dollar}20{dollar}spcirc{dollar}C, {dollar}-{dollar}30{dollar}spcirc{dollar}C, and {dollar}-{dollar}40{dollar}spcirc{dollar}C. Mackerel were packed in air or vacuum with or without an ascorbate dip. With white hake tripolyphosphate was substituted for ascorbate.; Frame minces for all species were found to be significantly higher in iron than fillets or H&G minces. Fillet minces had higher iron than unminced fillets, and fillets with the skin on had higher iron than skinless fillets. Mackerel had comparatively more iron than lean fish. A serving size of 100 g of mackerel fillets with skin on would provide 7% to 9% of the female iron RDA, while fillets without skin would provide 5% to 6%. H&G and frame mackerel minces provide 9% to 11% of the iron RDA. Fillets from both lean species, on the other hand, would provide less than 2% of the RDA for iron per 100 g serving. H&G or frame minces obtained from these lean species would provide 7% to 8% of the same RDA per 100 g serving. Frame mince, which is an unused source of edible food, in addition has 20-50% of the total iron as highly available heme iron.; The frozen storage and packaging studies suggested that the nonheme iron fraction increased due to release of iron from the heme molecule. It occurs at a faster rate at temperatures above {dollar}-{dollar}20{dollar}spcirc{dollar}C, probably through an oxidative mechanism since vacuum and ascorbate helped maintain a higher heme iron content than air packaging.