Effect of Spice Treatment on the Quality of Solar Dried African Catfish, Clarias Gariepinus (Burchell, 1822) In Sokoto, Nigeria

Abstract

An experiment was conducted to determine the efficiency of garlic and ginger spice mixtures at 0%, 1%, 2%, and3% levels (per gram of fish) in retarding lipid oxidation on the proximate composition, Total Volatile Bases Nitrogen, Microbial level and organoleptic quality of solar dried catfish (Clarias gariepinus) in Sokoto, Nigeria. Fresh fish samples were purchased and washed thoroughly to remove sand and slime; they were humanely killed and eviscerated. Muscles of bigger fish were silt and dipped in 15% brine for 10 minutes. They were then divided into four batches S0 S1, S2, and S3 (replicated three times) representing un-spiced, 1% spiced, 2% spiced, and 3% spiced respectively then Solar dried at 45 °C for 6 days, cooled, stored at room temperature (26°C -32°C) for 5 weeks and used for proximate analysis, Total Volatile Bases Nitrogen, microbial and sensory evaluation analysis. Untreated samples served as control treatment. The results of this research indicated that samples treated with garlic and ginger mixtures (1:1 ratio) were microbiologically more stable than the control samples as these had longer shelf-life and were not covered by visible mouldy mass of mycelium during the five week storage period. The anti-oxidant activity of garlic, or garlic and ginger spice mixtures was evident from lower Total Volatile Bases Nitrogen (TVBN) values of treated samples relative to untreated (control) samples. Results of sensory evaluation showed a general preference for spice-treated samples. In conclusion, ginger and garlic, two abundant spices in this geographical zone, when combined, as paste, in solar dried Clarias gariepinus exhibit anti-oxidant and anti-fungal properties especially at 3% (per weight of fish). It is therefore recommended that in preservation of fish, 3 percent ginger and garlic mixture in addition to salting should be used to prevent fish spoilage.