MODELING THE DRYING BEHAVIOR OF UNSALTED AND SALTED CATFISH (ARIUS SP.) SLABS

The effect of air temperature on the drying behavior of unsalted and salted catfish (Arius sp.) slabs (10 x 5 x 1 cm) was investigated. Drying at 30 and 40C occurred in both the constant rate and falling rate periods, while drying at 50 and 60C occurred in the falling rate period only. Drying rate constants increased from 0.0474 to 0.2352 1/h for unsalted slabs and from 0.0819 to 0.3038 1/h for salted slabs as drying temperature increased from 30 to 60C. Diffusion coefficients increased from 1.61 to 5.79 x 10(-10) m(2)/s in unsalted slabs and from 2.31 to 8.55 x 10(-10) m(2)/s in salted slabs. Six mathematical thin layer drying models were applied to the moisture ratio data and the two-term model gave the best prediction. The rehydration ratio averaged 1.20 and 1.22 for unsalted and salted slabs, respectively. A drying temperature of 50C for 8 h is recommended.