نوع مقاله : مقاله پژوهشی
نویسنده
مکانیک بیوسیستم، دانشکده مهندسی زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
In this research, the parameters and kinetics of drying red delicious apple slices were investigated in a dryer equipped with a heat pump at different temperatures (30, 40, 50, 60 and 70 ͦC) and air velocities (1, 1.5 and 2 m/s). Analysis of variance was used to determine the effects of temperature and air velocity on the parameters of color change, shrinkage and intensity of reabsorption. Five mathematical models were selected to describe and compare the drying kinetics of apple slices, and the coefficient of determination (R2), chi-square (χ2), and (RMSE) were used for evaluation. The results showed that the temperature and speed of drying air had a significant effect on the drying behavior of apple slices. Drying time decreased with increasing temperature and drying speed. Temperature and air velocity had little effect on the total color changes, shrinkage rate and intensity of reabsorption of dried apple slices. Among the mathematical models, the modified Page model with the lowest error and the highest coefficient of determination had the best fit. Moisture transfer from apple slices was described by applying the Fick's diffusion model. The effective diffusion coefficient (Deff) increased with increasing drying temperature and was obtained in the range of 2.32 ×10-10 to 5.18 × 10-10 m2/s. The effective temperature dependence was described by the Arrhenius equation and the activation energy for moisture diffusion in apple slices was determined to be 28.4 kJ/mol.
کلیدواژهها [English]
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