Drying Kinetics and Mathematical Modeling of Algerian Red-Hot Pepper (Capsicum Annuum L.) Utilizing Microwave Radiation

Background: Drying is considered a good practice to preserve fruits and vegetables from spoilage and microbial growth. So, their use can be extended after the harvest periods. Capsicum annuum L. is a popular spice, but it cannot be stored in its fresh state due to its high moisture content. This is where the importance of microwave drying as a developed method lies. Aims: This study focuses on the characteristics of drying kinetics of red-hot peppers using a microwave oven under various microwave powers to analyze drying parameters. Drying models help to better understand the drying behavior. Methods: Different powers were used in the drying process. Moisture losses in the samples were recorded periodically to their equilibrium moisture. Drying parameters were calculated using mathematical equations. The experimental data were fitted to sixteen thin-layer models. Results: The characteristics of drying kinetics were determined microwave drying time decreased notably from 80 to 24 with the increasing power from 200 to 1200 in two main stages a warming-up and a falling-rate phases. Drying rates ( ) increased progressively during the initial drying stage (0.1152 and 0.4012 for 200 and 1200 , respectively) then decreased substantially during the final stage. A third-order polynomial relationship was found to correlate the effective moisture diffusivity with moisture content. The effective moisture diffusivity ( increased significantly with microwave power with the decrease in the moisture content (2.83 (×10-8) ± 0.1834 and 12.9 (×10-8) ± 0.2637 for 200 and 1200 . respectively). The calculated energy activation was found 23.48 ± 0.987 . The least specific energy consumption ( ) increased with increasing powers (1.55 (×10+8) ± 0.01 and 2.76 (×10+8) ± 0.0153 H2O for 200 and 1200 , respectively). Conversely to the energy efficiency values ( ) (14.55 (×10-4) ± 0.0881 and 7.84 (×10-4) ± 0.0078 % for 200 and 1200 ). The Hii model was found to be the best fit to describe microwave drying kinetics. Conclusions: Microwave drying has several advantages, such as drying time reduction and less energy consumption, while achieving higher drying efficiency at a moderate power level. Therefore, this innovative process is recommended in industrial food processing. Keywords: Capsicum annuum L.; Drying Kinetics; Mathematical Modeling; Diffusion; Activation Energy; Energy Consumption.