Determination of temperature dependent drying parameters for potato cylinders and slices during solar drying

In the present work, a methodology for the determination of temperature dependent drying parameters namely drying constant and lag factor from the experimental drying kinetic curves of food product is proposed. A laboratory scale mixed-mode solar dryer consisting of an inclined flat plate solar collector connected in series to a drying chamber glazed at the top was used to perform natural convection drying experiments with potato cylinders of length 0.05 m and diameter 0.01 m and slices of diameter 0.05 m and thickness 0.01 m. The thin-layer drying equation describing the drying behavior of food products is derived from Fick’s law of diffusion. The present analysis reveals that both drying constant and lag factor increase with sample temperature, as expected. Linear and exponential correlations for these parameters are proposed to represent their variation as a function of sample temperature. Results of statistical error analysis indicate that the proposed linear correlation can better represent the experimental drying kinetic curves for both cylinders and slices. Comparison of experimental dimensionless moisture contents with those calculated with variable (temperature dependent) and constant values of drying parameters demonstrates that the predicted results from variable parameters can better simulate the experiments.