This is aimed at studying the aeration kinetics of catfish (Clarias gariepinus) smoked directly with biogas. Five live fresh fishes (Clarias gariepinus) were obtained from Fishery and Aquaculture Technology Department in FUTA, Ondo State, Nigeria. The fishes were killed, de-gutted, thoroughly washed with water, cut into pieces of 3 cm length. The chunks were smoked with biogas and the weight was being monitored at 15 minutes interval until constant weight was observed.. The study showed that the time taken for drying of Clarias gariepinus to reach the humidity point of around 12.43% (db.) was two and a half hours. We tailored the drying data to 10 thin-layer drying models. The compared the performances of the models using the determination of coefficient (R2), reduced chi-square (χ2) and root mean square error (RMSE) between the detected and foreseen moisture ratios. The results showed that Henderson and Pabis modified model was found to satisfactorily describe the biogas drying curves of Clarias gariepinus.
The fermentation conditions for the production of “pupuru” are enhanced at optimized conditions using response surface methodology (RSM). A Central Composite Design (CCD) with three independent variables; mass of root (2 to 6 kg), fermentation temperature (28 to 32 oC) and fermentation time (72 to 120 h) are used to study the response variables pH and Total Titratable Acidity (TTA) of fermented cassava. The design gives nineteen runs, 5 centre points, 14 non centre points. A face centred central composite second - order design is used to evaluate the combined effect of the independent variables. The results indicate that the generated regression model represents the relationship between the independent variables and responses. All linear terms, two quadratic terms (fermentation time and fermentation temperature) and all interactive terms had insignificant (p < 0.05) effect on pH and TTA. The optimum conditions for fermentation are achieved at 28 oC for 105 h to obtain pH of 3.99 and TTA of 0.25% Lactic acid which shows no significant difference (p>0.05) from the response surface methodology predicted pH and TTA of 3.96 and 0.22% Lactic acid.