In this work, mathematical modeling of infrared drying of thin-layer lemon slices with 5±1 mm thickness was investigated. Thin-layer drying was conducted under four different drying temperatures (100, 125, 150 and 175 °C) at absolute humidity of 0.6 ± 0.02 g of water/kg of dry air. The results revealed that the drying process occurred in falling rate period over the drying time. Moisture transfer from lemon slices was described by Fick’s diffusion model. The effective diffusivity for lemon slices was within the range of 9.9 ×10-10 to 2.76×10-9 m2/s over the temperature range. The activation energy was found to be 87.61 kJ/mol indicating the effect of temperature on diffusivity. Eight well-known thin-layer drying models were fitted to the drying experimental data of lemon slices, implementing non-linear regression analysis techniques. Based on the statistical analysis using coefficient of determination (R²) and root mean square error (RMSE), it was concluded that the best model in terms of fitting performance for infrared drying of lemon slices at all selected temperatures were Wang and Sing model.

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