Mathematical Modeling of Tilapia Fish Fillets Dried in Thin Layer

This work aimed to evaluate using hot air for drying of fresh tilapia fillets. Effect of the drying temperature (40, 50, 60, and 70°C) on the moisture ratio and drying rate has been investigated. A constant level of air flow rate of 0.087 m 3 s -1 was used and constant dimensions for tilapia fillets of 80 x 30 x 5 mm of length, width and thickness respectively. Seven different widely used thin layer drying models were fitted to the experimental drying data of fresh tilapia fillets under different conditions using nonlinear fitting techniques. Four statistical parameters, including coefficient of determination, standard error, reduced chi-square, and root mean square error, were used to compare all models. The obtained results showed that the drying process took place in falling rate periods. The result also showed that average value of determination coefficient in exponential linear combination model was 0.9988, and standard error, root mean square error and corresponding reduced chi-square values were 0.106, 0.0096 and 0.0001, respectively, which indicated that “exponential linear combination model” is the best of studied models for describing drying curves of fresh tilapia fillets. Meanwhile, effective moisture diffusivity D eff increased by increasing drying air temperature and its value ranged from 3.47 to 6.86 10 -10 m 2 s -1 , whereas drying activation energy value was 20.148 kJ/mol for the studied