Proximate Composition of Fresh and Smoked-dried Gymnarchus niloticus from Markets Along the Orashi River, Rivers State, Nigeria

Abstract

This study evaluated the proximate composition of fresh and smoked-dried Gymnarchus niloticus obtained from three markets along the Orashi River axis of Rivers State, Nigeria: Mbiama, Ndoni, and Omoku. Eighteen samples were collected monthly for three months, comprising three fresh and three smoked-dried samples from each location, and were analysed using standard proximate analytical procedures. The data were subjected to one-way analysis of variance, and mean separation was performed using Duncan's multiple range post-hoc test at P < .05. The results showed that smoke-drying significantly influenced the proximate composition of the fish samples. Moisture content was higher in fresh samples, ranging from 65.89% in Mbiama to 70.53% in Omoku, but declined markedly in smoked-dried samples, with values ranging from 13.99% in Ndoni to 18.26% in Mbiama. Crude protein increased after smoke-drying, from 14.98-18.83% in fresh samples to 65.08-72.40% in smoked-dried samples, indicating concentration associated with moisture reduction. Ash content also increased from 1.89-2.40% in fresh fish to 5.43-6.86% in smoked-dried fish, suggesting a relative increase in mineral concentration. Crude fat and carbohydrate contents generally decreased after drying, although the extent of change varied among the markets. Crude fibre showed smaller changes, with values differing across sample form and location. Significant differences were observed among samples from different locations and between processing forms, indicating that both market origin and smoke-drying contributed to variation in proximate composition. The findings provide baseline compositional information on G. niloticus from the Orashi River markets and show that smoke-drying substantially changes its moisture, protein, ash, fat, fibre, and carbohydrate profiles.