Kinetic Modeling of Convective and Microwave Drying of Potato Peels and Their Effects on Antioxidant Content and Capacity

This study deals with drying properties and focuses on the drying kinetics of potato peels (PP) by two processes, namely convection drying (CD) at various temperatures (40, 60, 80, 100, and 120 degrees C) and microwave drying (MD) at different powers (200, 400, 600, and 800 W). In addition, the effectiveness of the adopted processes was evaluated in terms of antioxidant contents and antioxidant capacity. A total of 22 mathematical models were undertaken to predict the drying kinetics, and the best model was selected based on the highest R-2 values and the lowest chi(2) and RMSE values. The Sledz model was the more appropriate for both methods with values of 0.9995 <= R-2 <= 0.9999, chi(2) = 0.0000, and 0.0054 <= RMSE <= 0.0030 for CD, and the results of MD were 0.9829 <= R-2 <= 0.9997, 0.0000 <= chi(2) <= 0.0010, and 0.0304 <= RMSE <= 0.0053. The best drying rates (DR) of PP were assigned to a temperature of 120 degrees C and a power of 600 W with values of 0.05 and 0.20 kg water/kg dw min, respectively. A potential explanation is that as PP's moisture content decreased during the drying process, there was a drop in absorption, which led to a reduction in the DR. The energy consumption of both processes was assessed, and it rose with increasing temperature or power. The microwave process reduced the drying time, consumed lower energy, and presented a higher drying efficiency at a moderate power level compared to the convection process. Furthermore, MD preserved antioxidants better compared to CD and improved the antioxidant capacity. Therefore, the proposed microwave process for drying PP is suggested for its expected use in various fields, including the food processing industries.

Automated summary

This study investigates the drying properties of potato peels (PP) using two different processes: convection drying (CD) and microwave drying (MD). The drying kinetics were analyzed at various temperatures for CD and different powers for MD. The study also evaluated the effectiveness of these processes in terms of antioxidant contents and capacity. A total of 22 mathematical models were used to predict the drying kinetics, and the Sledz model was found to be the most suitable. The best drying rates for PP were achieved at a temperature of 120 degrees C and a power of 600 W. The energy consumption increased with higher temperature or power. MD showed shorter drying time, lower energy consumption, and better preservation of antioxidants compared to CD. The proposed microwave drying process for PP is recommended for various industries, including food processing.