Optimisation of loading capacity of smoking kiln on drying characteristics of Catfish (Clarias gariepinus)

Fish smoking is widely used in the fish processing industry, especially in the post-harvest catfish product due to its simple operating technique. The objective of this study was to optimise the tray loading capacity of a smoking kiln for catfish. A mixture design was employed to investigate the effects of varied fish size (0.25, 0.30 and 0.35 kg) component tray loading on the loading capacity, drying rate and moisture ratio during smoking process. The results showed that the loading capacity of the kiln was between 190 and 198 pieces of fish at minimum and maximum 50 and 52 kg. High moisture ratio was observed at equal size combination at low drying rate. The catfish weight mixtures of 0.25, 0.30 and 0.35 kg used to evaluate the kiln load capacity optimization were significant (P < 0.05). The smoking kiln worked optimally at catfish size (50, 50 and 0 %) with maximum desirability of 0.63 resulted in weight of fish loaded of 51.30 kg, moisture ratio of 0.21 and drying rate of 0.5 kg⁻¹ h. This study brings new knowledge about the loading capacity and confirms that the smoking kiln is an acceptable technology for processing fish.