Study of the drying behaviour in peeled and unpeeled whole figs

Aim of this study was to estimate the effect of peeling on drying kinetics and effective diffusivity D_eff of figs (Ficus carica L. var. tsapela) during air-drying. For this purpose three temperatures (45, 55 and 65 °C) were tested. The Logarithmic model was chosen to describe the drying curves among seven drying models. The estimated drying constants were associated with the drying temperature by an Arrhenius type equation. The ratio of peeled to unpeeled relaxation times was found to be 0.54 ± 0.16. The D_eff of figs (peeled and unpeeled) was estimated by the method of slopes. The D_eff of the peeled figs was higher than this of the unpeeled figs presenting smaller differences as drying temperature was increased. This behaviour was attributed to the case hardening effect which is faster developed as the drying rate increases during high temperature drying.