Convective and microwave drying kinetics and modeling of tomato slices, energy consumption, and efficiency

Abstract

This investigation presented presents the drying characteristics, and aimed to predict the drying kinetics of tomato slices (Lycopersicon esculentum MILL.) using convection and microwave methods. Hot air drying was carried out in a ventilated oven at 50, 60, 80, and 100°C temperatures and microwave drying was performed in domestic microwave using 300, 500, 800, and 900 W powers. Twenty‐two mathematical models were undertaken to predict the drying kinetics and the best model was chosen based on the highest R2 values and the lowest root mean square error (RMSE) and χ2 values. Drying kinetics, drying rate variation, diffusivity and energy consumption of both methods were evaluated. Fernando and Amarasinghe model and Sledz model were the best models for convective and microwave drying processes, respectively. Effective moisture diffusivity varied from 0.28 × 10−9 to 2.81 × 10−9 and from 1.32 × 10−9 to 21.52 × 10−9, while the activation energy was 27.64 kJ/mol and 5.71 W/g for convective and microwave drying processes, respectively. The energy consumption increases with increasing temperature or power, the reverse was observed for energy efficiency. Microwave drying process has the advantage of drying time reduction, low‐energy consumption, and high‐drying efficiency at a moderate high‐power level (900 W). Hence, it is recommended to apply this innovative process for drying tomato slices.

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

“…The mathematical modeling was accomplished, and 22 drying models were identified ( Table 1 ). The obtained equations are related to the moisture ratio (MR) as a function of time as well as the drying rate (DR), effective moisture diffusivity (D eff ), specific energy consumption (SECe), and energy efficiency (EE), and they were presented in our previous report [ 10 ]. The formulas used to calculate the determination coefficient (R 2 ), chi-square (χ 2 ), and root mean square (RMSE) were also reported by the same authors.…”

“…Drying is reputed as a crucial factor for the successful preservation and merchantability of raw materials, and its procedures constitute substantial phases in the food and chemical transformation industries [ 9 ]. Dehydration of by-products consists of removing water up to a defined amount, usually about less than 15%, to avoid microbial deterioration and to reduce the degeneration caused by biochemical reactions [ 10 ]. However, drying procedures can generate modifications that impact on by-product quality.…”

“…In recent years, microwave drying has attracted attention as a substitute drying technique in the agri-food industries. It is fast, more homogeneous, and more power effective compared to conventional methods [ 10 , 12 , 13 , 14 , 15 ].…”

Influence of convective and microwave drying on Algerian blood orange slices: Drying kinetics and characteristics, modeling, and drying energetics

“…Higher of ( R 2 ), smaller of χ 2 , smaller of RMSE, and a random distributed of residual indicate the adequacy of the experimental data to the model. The statistical values are determined as follows (Guemouni et al, 2022): where MR exp is experimental moisture ratio (dimensionless), MR pre is predicted moisture ratio (dimensionless) and equilibrium moisture content, respectively, and N is the number of data points and Z is the number of the constant parameters in the thin‐layer drying models (Agbede et al, 2020; Krishna Murthy & Manohar, 2012). Analysis of variance (ANOVA) was performed using JMP 13 software.…”

“…Higher of (R 2 ), smaller of χ 2 , smaller of RMSE, and a random distributed of residual indicate the adequacy of the experimental data to the model. The statistical values are determined as follows (Guemouni et al, 2022):…”