Modeling of microwave drying kinetics of yam

The effect of microwave power and mass in the drying of slices yam (Dioscorea rotundata) of 1cm thick and 3 cm in diameter was evaluated. The chips were subjected to three different powers, 420W, 560W and 700W; with three different masses 50g, 60g and 70g. The drying time, the kinetics of drying, the coefficient of thermal diffusivity and the activation energy were measured. Treatments showed a highly significant effect of the power and the mass on drying time (p<0.05). The Midilli and Kucuk's model is best to describe the drying kinetics (average squared error<0.01 and linear correlation coefficient>0.99) Drying times were reduced when treatment intensity was higher and the effective diffusivity coefficient presented values between 1.83x10-4 to 9.41x10-4 m2/s and activation energy of 22.38W/g.