ABSTRACT

Moisture content is an important quality feature that directly influences the storability of fruits and vegetables. The main goal of the present study was to estimate the drying behavior of apple slices (Malus Domestica) in a laboratory dryer at the drying temperatures of (40.9, 45, 55, and 65°C) and the time interval of (155.2, 180, 240, 300 and 324.9 minutes) with response surface method. The response surface methodology is used to optimize the dehydration of apple slices, and three thin-layer drying models are applied to the drying data. The effect of drying temperature and time interval tested at three levels on the percentage of moisture content, drying rate, hardness, and rehydration ratio were determined, with R² values of 0.0761, 0.0519, 0.0564, and 0.2341, respectively. From the results, the actual optimum drying temperature with a time interval of 55°C and 240 min was better suited for the dehydration of apple slices. Therefore, the exact values of moisture content, drying rate, hardness, and rehydration ratio were noted in 11.40%, 0.030 (g_water. g_{dry. matter}⁻¹ cm⁻² min⁻¹), 2.35 N m, and 1.03 with a run factor of seven, respectively. Newton, Henderson & Pabis, and Page mathematical models are applied to the drying data, and consistent quality of the proposed models determined by using the calculation of the coefficient of determination (R²), reduced chi-square (X²), and root mean square error (RMSE). Further, from the results, it was conducted that the Newton model was better describing the data with R², X^2, and RMSE values of 0.9989, 0.00014, and 0.0145, respectively, of the apple slices. This manuscript will be helpful for researchers working on commercializing Apple slice processes in China as well as in other countries.