Effect of High-Pressure Processing and Frozen Storage Prior to Canning on the Content of Essential and Toxic Elements in Mackerel

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 (Scomber scombrus) was studied. Previous frozen storage led to an increased (p < 0.05) content of canned samples of K (oil-coated samples) and Ca (all coating conditions) and to a decreased (p < 0.05) content of P (aqueous-coating samples) and S (water- and oil-coated samples). For trace elements, a content increase (p < 0.05) in Cu and Se (brine-canned samples) and Mn (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 (p < 0.05) Mg, P, S, K, and Ca contents than their corresponding oil-coated samples. For trace elements, lower average contents were found for Co, Cu, Mn, Se, and Fe 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).