The content and nutritional significance of minerals on fish flesh in the presence and absence of bone

The aim of the present study was to evaluate the variations in the mineral contents (Fe, Zn, Cu, Mn, Na, K, Ca, Mg and P) and nutritional significance of the minerals of Mediterranean fish, as a function of the presence of bone. The three commercial species analysed were blue whiting (Micromessistius poutassou;R), hake (Merluccius merluccius, L) and sole (Solea vulgaris vulgaris, Q). As small and large species of hake are distinguished commercially, they were analysed as separate types of fish. No variations in the contents Fe, Zn, Cu, Na and K were observed when bone was included, as the content of trace elements were quite low in all the samples assayed. However, significant increases in the Ca and P contents were observed in all the species analysed when bone was included. To ascertain the nutrional significance of the samples they were considered as ingredients of fish-based homogenised weaning foods. According to the Ca and P contents, and to the nutritional density values, the samples could be considered to be good supplements of Ca and P, when bone is present in the flesh.