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This work focused on the effects of the moisture content, slices thickness and microwave power on aspects of energy and exergy, drying kinetics, moisture diffusivity, activation energy, and modeling of the thin layer drying of kiwi slices. Results showed that energy and exergy efficiency increased with increasing microwave power and decreasing slice thickness while values of energy efficiency (15.15-32.27 %) were higher than exergy efficiency (11.35-24.68 %). Also, these parameters decreased with a decrease in moisture content. Specific energy consumption varied from 7.79 to 10.02, 8.59 to 10.77 and 9.57 to16.20 to MJ/kg water evaporated for 3, 6 and 9 mm, respectively. The values of exergy loss were found to be in the range of 5.90 and 14.39 MJ/kg water and decreased as the microwave power increased and slice thickness decreased. Effective diffusivity increased with decreasing moisture content and increasing microwave power and slice thickness. Average effective moisture diffusivity of kiwi slices changes between 1.47 × 10

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The energy and exergy analysis, drying characteristics and mathematical modeling of the thin-layer drying kinetics of white mulberry using microwave drying were investigated. Results indicated that values of exergy efficiency (33.63–57.08%) were higher than energy efficiency (31.85–55.56%). Specific energy consumption increased with increasing microwave power while improvement potential decreased. The specific energy consumption and improvement potential varied from 3.97 to 6.73 MJ/kg water and 0.71 to 2.97 MJ/kg water, respectively. Also, energy efficiency decreased with decrease in moisture content and microwave power level. The best exergy and energy aspect was obtained by drying at 100 W microwave power. Drying took place mainly in warming up, constant rate and falling rate periods. The Page model showed the best fit to experimental drying data. Effective diffusivity increased with decreasing moisture content and increasing microwave power. It varied from 1.06 × 10−8 to 3.45 × 10−8 m2/s, with an energy activation of 3.986 W/g.

In this study, infrared drying characteristic of mushroom slices was investigated in the temperature range of 50–90°C. The drying data were fitted to five thin-layer drying models. The performance of these models was compared using the determination of coefficient (R2), reduced chi-square (χ2), and root mean square error between the observed and predicted moisture ratios. The values of the diffusivity coefficients at each temperature were obtained using Fick’s second law of diffusion. The drying processes were completed within 60–168 min at different temperatures. Experimental drying curves showed only a falling drying rate period. The results show that the logarithmic model is the most appropriate model for infrared drying behavior of thin-layer mushroom slices. A third-order polynomial relationship was found to correlate the effective moisture diffusivity with moisture content. The average effective moisture diffusivity increased with increasing temperature and decrease in moisture content of mushroom slices and varied from 8.039 × 10−10 to 20.618 × 10−10 m2/s. Arrhenius relation with an activation energy value of 21.85 kJ/mol expressed the effect of temperature on the average diffusivity. The minimum and the maximum energy requirements for drying of mushroom slices were also determined as 2.87 kW h/kg water and 5.36 kW h/kg water for 90 and 50°C, respectively.

In this research, drying characteristics, energy requirement and drying efficiency for microwave drying of potato slices were reported. The drying experiments were carried out at 200, 250, 300, 350, 400, 450 and 500 W with slice thickness of 5 mm. In this study, measured values were compared with predicted values obtained from Page's thin layer drying semi-empirical model according to R 2 , χ 2 and RMSE. The increase in microwave power significantly reduced the drying time from 9.5 to 3.25 min of the potato slices. Experimental drying curves showed only a falling drying rate period. A third order polynomial relationship was found to correlate the effective moisture diffusivity (D eff) with moisture content. The values of drying rate constant (k) and D eff increased from 0.105 to 0.322 (1/min) and 1.013×10-8 to 3.799 ×10-8 m 2 /s with the increase of microwave power level, respectively. Also, the effective moisture diffusivity increased with decrease in moisture content of samples. The activation energy for the moisture diffusion was determined to be 14.945 W/g. Drying efficiency increased with increase in microwave power and moisture content. The minimum and the maximum specific energy consumption and drying efficiency for drying of potato slices were determined as 4.645 (MJ/kg water) and 48.59% for 500 W and 5.882 (MJ/kg water) and 38.37% for 300 W, respectively.