Effect of Previous Frozen Storage and Coating Medium on the Essential Macroelement and Trace Element Content of Canned Mackerel.

The effect of previous frozen storage (-18 °C for 6 months) and different coating media (aqueous: water and brine; oily: sunflower, refined olive, and extra-virgin olive oils) on the essential macroelement and trace element content of canned Atlantic mackerel () was studied. Previous frozen storage led to an increased ( < 0.05) content of canned samples of (oil-coated samples) and (all coating conditions) and to a decreased ( < 0.05) content of (aqueous-coating samples) and (water- and oil-coated samples). For trace elements, a content increase ( < 0.05) in and (brine-canned samples) and (water- and refined-olive-oil-coated samples) was detected in canned fish muscle with frozen storage. Concerning the coating effect, aqueous-coating samples showed lower ( < 0.05) , , , , and contents than their corresponding oil-coated samples. For trace elements, lower average contents were found for , , , , and in aqueous-coating fish muscle when compared to their counterparts coated in oily media. Content changes in the different elements in canned fish muscle are discussed based on interactions with other tissue constituents and modifications that such constituents undergo during processing (i.e., protein denaturation, liquor losses from the muscle, lipid changes).