Study the effect of microwave power and slices thickness on drying characteristics of potato

Abstract

In the present work, the influence of microwave power and samples thickness on drying behavior, moisture diffusivity and energy consumption of potato slices was studied. The slices with thicknesses of 3.5, 5, 7 and 9 mm were dried as mono layers at four different power levels (200, 400, 600 and 800 W). The results showed that the process time was significantly (P < 0.05) decreased with increasing power and decreasing thickness. The curves of moisture removal rate included a short accelerating rate period at the beginning followed by a long falling rate period. Seven thin layer models were practiced to simulate the experimental drying kinetics and the Midilli model showed the best performance. The average values of effective moisture diffusivity were obtained to be in the range of 1.15510−8-6.654 × 10−8 m2 s−1, and increased significantly (P < 0.05) with both of the increasing microwave power and the samples thickness. The average activation energies changed from 1.423 W g−1 to 1.621 W g−1, and decreased with increasing samples thickness. Specific energy consumption for the process were ranged from 0.680 MJ kg−1water to 2.591 MJ kg−1water.