COMPARATIVE DRYING KINETICS AND MOISTURE DIFFUSION OF ALBANIAN AND ITALIAN ORANGE PEELS: A MATLAB–BASED ANALYSIS

The study carries out a mathematical comparison of the drying behaviour of orange peels from Albania and Italy under various thermal conditions and for different sample sizes. Peel samples having characteristic dimensions of 5, 10, and 15 mm were dried at 50, 100, and 150 °C in a thermostat and at 95 °C in a convective dryer. The experimental mass data were processed in MATLAB in order to determine the moisture content, the moisture ratio (MR), the drying rate (DR), and the apparent effective moisture diffusivity (Deff). The moisture transport was interpreted by means of the linearised solution of Fick\'s second law for slab geometry. In both cases, drying took place mainly during the falling-rate period, which indicates that internal moisture diffusion was the main controlling factor. Higher temperatures had a marked effect in speeding up the removal of moisture, and the 5 mm samples generally attained equilibrium sooner than the 10- and 15-mm samples. Differences associated with the origin of the peels were also found. At 50 °C the Italian peel dried more quickly and matched the Fick diffusion model representation more closely. At 100 °C the Italian samples showed more variable behaviour depending on their thickness, while the Albanian ones displayed a more consistent response with respect to dimension. When dried convectively at 95 °C, the Italian peel lost moisture more rapidly, especially in the case of the 5- and 10-mm samples. The findings show that the drying behaviour is determined by the combined influence of temperature, characteristic dimension, drying method, and the origin of the material. The MATLAB–Fick approach offers a practical way of comparing moisture-transport behaviour, while the deviations observed at high temperature point to the necessity of taking into account shrinkage and structural changes in future modelling.