Vacuum Drying of Barberry Fruit (<em>Berberis vulgaris</em>) and Selection of a Suitable Thin Layer Drying Model

Abstract

In an investigation on kinetics of seedless barberry drying at 35, 45 and 55°C in vacuum and with water vapor and citric acid pre-treatments, the value of effective moisture Diffusivity (D_eff) was calculated using the second Fick's diffusion equation, activation energy was determined and drying process was simulated by 10 common mathematical equations of thin layer-drying models. Results which were obtained from regression analysis of studied models showed that approximation of diffusion model had the best fitting for vacuum-drying of barberries through available data. Drying barberry took place in the falling rate drying period and pre-treated samples had higher drying rate. The effective diffusivity coefficient for vacuum-drying of barberry fruits was evaluated between 0.0228×10^-10 and 0.2538×10^-10 m²/s, which increased along with temperature rise. An Arrhenius equation for drying of seedless barberry with activation energy values ranged from 27.618 to 92.493 kJ/mol expressed the effect of temperature on moisture diffusivity.