Mineral Content in Baltic Herring and Baltic Herring Products

The contents of Fe, Cu, Zn, Mn, K, Mg, Ca, Na, As and Cd in gutted Baltic herring (Clupea harengus membras), in Baltic herring fillets and in two commercial ready-to-eat products made of these were investigated. The fish was caught in 1996–1998 in the northern Baltic. The commercial products were fried fillets and fish burgers. The effects of industrial processing on the mineral composition were studied by collecting samples at several consecutive stages. In the gutted fish the levels of Mn, Ca and Cd were considerably higher than in the fillet mainly due to the bones. Significant differences were also observed in the contents of Mg, Na, Cu and Zn. In the burger process the bones and skin were removed which caused a decrease in the Zn and Ca levels. Ingredients such as salt, spices and flour as part of the formula increased Na and Mn contents in the ready-to-eat products. In the final products the Na content was about 6 times higher than that of the fresh fish.