Studies on some major and trace metals in smoked and oven-dried fish
Ako, P.A.; Salihu, S.O.
Journal of Applied Science and Environmental Management 8(2): 5-9
2004
Document Number: 259977
The mineral (lithium, sodium, potassium, calcium, magnesium, iron, copper, manganese, zinc and lead) composition of fish (Sarotherodon galilaeus, Cyprinus carpio, Clarias gariepinus, Sardinella spp. and Labeo spp.) dried either by traditional smoking or in laboratory oven was determined. The fish samples were purchased from markets in Minna, Niger State, Nigeria. Portions of whole fish meals were digested in a nitric acid-hydrogen peroxide-perechloric acid (3:11) mixture and the digests were analysed using spectrophotometry. The concentration of lead was lowest in both smoked and oven-dried specimens with mean values of 0.46-1.16 and 0.54-0.76 mg/kg, respectively; whereas calcium concentration was highest with mean values of 592.98-7553.55 and 498.65-6460.85 mg/kg, respectively. Comparative studies showed that no significant differences existed between the mineral contents of smoked and oven-dried samples, except in few cases: lithium in Sarotherodon galilaeus, zinc in C. gariepinus, copper and manganese in Cyprinus carpio and Sardinella spp., and lead in Sarotherodon galilaeus. The smoked samples were consistently richer in mineral content, suggesting the need for chemical examination of products of this drying method.