An improved fish smoking kiln was designed and fabricated. Catfish samples were smoked using three biomasses, namely iron tree, sawdust and rice husk. Variations in utilizable temperatures with time, phenol contents, smoke density, weight loss, proximate composition and sensory qualities of the smoked fish were evaluated. The utilizable temperatures due to combustion of constant weight of each biomass ranged from 60 to 120C for sawdust, 61.5 to 132C for rice husk and 60 to 120C for iron tree in 5 h. The temperatures due to combustion of iron tree, rice husk and sawdust decline to a constant value. The temperature of iron tree showed steadier decline. The phenol content ranged from 0.42 to 0.48 mg/mL with rice husk having the highest value while iron tree had the lowest value. Smoke density ranged from 0.021 to 0.024 g/cm3 showing the same trend. Proximate analysis shows significant difference (P < 0.05) in moisture, protein, lipids and ash. However, carbohydrate content does not change significantly (P > 0.05). Organoleptically, catfish smoked with iron tree yielded the best quality and was significantly (P < 0.05) superior to that smoked with sawdust and rice husk. Samples smoked with sawdust were least preferred.
The oven would be used for drying of fish which will lead to the reduction of postharvest fish losses.