Effects of Temperature and Slice Thickness on Drying Kinetics of Pumpkin Slices

Dried pumpkin slice is an alternative crisp food product. In this study, the effects of temperature and slice thickness on the drying characteristics of pumpkin were studied in a lab-scale tray dryer, using hot air temperatures of 55, 60 and 65 °C and 2, 3 and 4 mm slice thickness at a constant air velocity of 1.5 m/s. The initial moisture content of the pumpkin samples was 900.5 % (wb). The drying process was carried out until the final moisture content of product was 100.5 % (wb). The results showed that the drying time decreased with increasing drying temperature, but it increased with increasing slice thickness of the pumpkin. In all tests, the experimental drying curves obtained show results for only the falling rate period. Fick’s diffusion equation has been used to model the drying characteristics and fits all experimental data. The effective moisture diffusivity during drying varied from 1.359×10-10 to 5.301×10-10 m2/s. The effective moisture diffusivity results were in agreement with previously reported diffusivity values.