Vacuum Drying Characteristics of Kiwi Fruit Leather (Lavashak)

In this experiment the drying of kiwi fruit leather was investigated in a laboratory scale vacuum dryer. The effect of drying temperature (60, 70 and 80°C) and sample thickness (5, 7 and 9 mm) on the drying characteristics was determined. Twelve thin-layer drying models were fitted to drying data and suitable model was selected from them. Then effective moisture diffusivity and activation energy of samples were calculated. The Midilli et al. model showed a better fit to the experimental drying data as compared to other models. The effective diffusivity values changed between 2.54×10-10 and 8.22×10-10 m2/s within the given temperature range. An Arrhenius type of equation was used to evaluate the effect of temperature on the effective diffusivity and the activation energy values was found 25 kJ/mol at different thicknesses of sample, approximately. All Hunter color parameters were influenced from drying conditions as increase in a* value and decrease in L* and b* values were observed.