Impact of different geometric shapes on drying kinetics and textural characteristics of apples at temperatures above 100 °C

The aim of this research was to determine the impact of samples size and shapes on drying kinetics, transport phenomena and textural characteristics of apples during drying. Three different geometric plate shape samples including squares, circles, and triangles, at temperatures of 110 °C, 115 °C and 120 °C, respectively, were dried at a constant air velocity of 1.75 m/s, and a nonlinear regression analysis was applied to fit the results to six dehydration models. The statistical analysis indicated that the Midilli & Kucuk model was the ideal model. Fick’s second law of diffusion was applied for computation of effective diffusivities, which varied from 1.93 × 10 −9 to 2.85 × 10 −9 m 2 /s, while the activation energy varied from 20.41 to 36.51 kJ/kg.mol. Additionally, the drag forces, heat and mass transfer coefficients varied from 4.202 to 5.005 N, 60.312 to 71.763 (W/m 2 K) and 0.0497 to 0.0594 (m/s), respectively. The results reveal that triangular shapes could have the potential to improve the air drying of apples at an industrial extent.