Low-temperature convective drying of apple cubes

Abstract

The paper presents results of an experimental investigation of convective drying of Idared apple in full recirculation laboratory scale dryer. The experiments were conducted with cube-shaped apple samples (side length 10 and 13 mm), without pre-treatment. The parameters of air stream over the tray with samples were fully controlled and adjusted in several sets of experiments, while always remaining in the following ranges: temperature 35-55 degrees C, relative humidity 10-30%, velocity 1-2 m/s. The drying kinetics of the apple samples was recorded, the results were analyzed and compared to the existing drying models. The analysis of the experimental results enabled derivation of correlations between drying parameters in a form k = f(T,RH), within Henderson & Pabis drying model MR = aexp(-k tau), as well as the calculation of effective moisture diffusivity during the process.