Influence of Drying Temperatures on Effective Diffusivity of Custard Apple Pulp

Abstract

Fresh custard apple pulp was dehydrated using convective drying method to study the effect of drying temperatures on effective diffusivity of custard apple pulp. Dehydration characteristics of custard apple pulp for the convective drying experiment were studied. Moisture diffusivity (Deff) at 50, 55, 60 and 65° C temperatures was ranged from 3.20 x10-9 m2/s to 4.80 x 10-9 m2/s and activation energy was found 29.436 kJ/mol at air velocity of 2 m/s. The average drying time was decreased 16.67, 10.00 and 22.22 for per 5 °C temperature increase. It was also found that greater drying effect of 22 per cent reduction in drying time was observed for 60 to 65 °C temperature increase. During the drying experiment and data were recorded, it was found that highest drying rate during the drying process was about thrice of the average drying time. It can be deduced from the study that drying process was fast at higher temperature and as the drying temperature increased the effective moisture diffusivity was also increased.