Drying kinetics and determination of effective moisture diffusivity and activation energy in cucumber pericarp tissues using thin-layer drying models

Abstract

The cucumber pericarp can be processed separately into diverse products due to the nutritional and mineral composition differing between layers. In this study, the drying characteristics of cumber endocarp and mesocarp tissues were investigated using various thin-layer drying models. Cubes of pericarp tissue were prepared from whole cucumber fruits. The results showed that drying rate increased with temperature and that a two-term model provided the best fit for the experimental drying data. The effective moisture diffusivity was estimated using a diffusion model and found to range from 5.0921 × 10⁻¹⁰ to 1.1426 × 10⁻⁹ m²·s⁻¹ and from 3.9123 × 10⁻¹⁰ to 8.9376 × 10⁻¹⁰ m²·s⁻¹ for cubes of endocarp and mesocarp tissue, respectively, at a drying temperatures ranging from 40 to 60 °C. Moreover, the variation observed in effective diffusivity was corrected by applying a shrinkage factor. The activation energy for endocarp and mesocarp tissues was 35.03 kJ·mol⁻¹ and 35.82 kJ·mol⁻¹, respectively.