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

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 (Deff) 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 10-10m2/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.