Convective drying of Jamun (Syzygium cumini) slices: role of drying conditions on drying kinetics and moisture diffusion

This study investigates the convective drying behavior of Jamun ( Syzygium cumini ) slices under varying drying air temperatures (60–80 °C) and velocities (1.0 and 1.5 m/s), with emphasis on drying kinetics, moisture diffusion, and model applicability. Experimental observations revealed that drying occurred entirely in the falling rate period, indicating that internal moisture diffusion governed the moisture removal process. An increase in drying temperature and air velocity significantly enhanced heat and mass transfer, resulting in faster moisture removal and reduced drying time by 16–17% at the higher air velocity of 1.5 m/s. Thin-layer drying models were evaluated to describe the drying characteristics of Jamun slices under different operating conditions. Among the tested models, the Page model demonstrated superior agreement with experimental data at higher temperatures, whereas the Midilli–Kucuk model showed better predictive capability at lower drying temperatures. The results confirmed the suitability of empirical thin-layer models for accurately representing the convective drying behavior of Jamun slices. In addition, effective moisture diffusivity increased with increasing temperature and airflow, highlighting the strong influence of process parameters on internal moisture migration and overall drying efficiency. These findings provide useful insights into optimizing convective drying conditions for Jamun slices while contributing to the scientific understanding of drying kinetics and moisture transport phenomena in agricultural products.