Evaluation of nutritional quality of smoked and oven dried African catfish (Clarias gariepinus) from Zobe reservoir, Katsina State, Nigeria

Abstract

This study investigated how hot-smoking and convective oven-drying affect the proximate and mineral composition of Clarias gariepinus. Significant differences were observed between the two processing methods. Thirty fresh fish samples were randomly split into two groups: 15 were smoked, and 15 were oven-dried. Proximate and mineral compositions were determined on a dry-weight basis, mineral contents were normalized to a wet-weight basis to account for differences in moisture content between processing methods, and data were all expressed as means ± SD. Data were analyzed using one-way ANOVA, and significant differences were identified with Duncan’s multiple range test at a 5% level of significance. Oven-dried fish retained higher moisture content (14.2 %) and showed increased crude protein (40.1 %) and lipid levels (22.0 %) compared with smoked samples, which were more dehydrated (5.3 %) and contained lower protein (33.7 %) and lipid (16.5 %) contents. Conversely, ash content was significantly higher in smoked fish (43.5 %) than in oven-dried samples (22.7 %). The processing method also influenced mineral composition. Oven-dried fish contained higher concentrations of calcium, magnesium, and potassium, whereas smoked samples were richer in iron and sodium. These differences are attributed to variations in dehydration intensity, heat exposure, and mineral concentration or deposition during processing. Overall, the results demonstrate that the processing technique plays a critical role in shaping the nutritional quality of preserved C. gariepinus, with important implications for dietary selection and fish processing practices.

Keywords: Clarias gariepinus, smoking, oven-drying, proximate composition, mineral content, nutrient quality