Air-drying and rehydration characteristics of date palm (Phoenix dactylifera L.) fruits

The influence of variety and drying temperature range of 50–80 °C on air-drying pattern of date palm fruits were investigated. Results indicated that drying took place in the falling rate period. Moreover, the effect of variety and rehydration temperature range of 15–45 °C, maintaining a fruit : water ratio of 1:25 w/w were also investigated. Moisture transfer during air-drying and rehydration were described by applying the Fick’s diffusion model, and the effective diffusivities and activation energies were calculated. Arrhenius relation with activation energy range of 35.17–44.02 and 30.29–40.29 kJ/mol expressed the effect of temperature on the diffusivities during air-drying and rehydration, respectively.