PHYSICO-CHEMICAL AND ELEMENTAL PROFILES OF SMOKE-DRIED FISH SPECIES SOLD IN IMO STATE, NIGERIA

Abstract

This study examined the physico-chemical properties and mineral elements profile of four common smoke-dried fish species in open markets in Imo State, Nigeria. The fish species were Gymnarchus niloticus (Trunkfish), Rita sacertodum (Thailand), Clarias gariepinus (African catfish) and Ethmalosa fimbriata (Bonga fish). Each of the fish species was analysed for their physico-chemical attributes and mineral profiles to ascertain their quality and safety. Basic physico-chemical attributes investigated include peroxide value (PV), total volatile basic nitrogen (TVBN) and pH. The PV values ranged from 4.62±0.03 - 32.97±0.05 mEq O2/kg in G. niloticus, 2.79±0.01 - 34.83±0.05 mEq O2/kg in R. sacertodum, 0.8±0.01-8.82±0.02 mEq O2/kg in C. gariepinus and 6.06±0.06-18.78±0.11 mEq O2/kg in E.fimbriata. The TVB-N values were within acceptable limits, from 7.29±0.1-10.36±0.1 mg/kg, 7.81±0.1-10.15±0.1 mg/kg, 5.75±0.18-10.40±0.25 mg/kg and 7.44±0.1-10.56±0.2 mg/kg for G. niloticus, R. sacertodum, C. gariepinus and E. fimbriata, respectively. pH values were above 7 except R. sacertodum (6.97) and E. fimbriata (6.92) found in the open market of Anara. The highest pH value was 7.99 in C. gariepinusin. The fish species contained elements reflecting the mineral composition of the water bodies they were harvested, and possibly contaminants from poor handling. Trace elements such as iron (Fe), copper (Cu), nickel (Ni), zinc (Zn), manganese (Mn), and chromium (Cr) were detected at varying concentrations. Fe, Cu, Zn, Mn, and Cr exceeded recommended limits in some locations; this may be a potential health risk. Arsenic (As) and lead (Pb), known for their toxicity, were not detected across all sample locations.