DRYING CHARACTERISTICS OF 'ANKARA' PEAR SLICES

This study evaluated the effects of drying temperature and pre-treatment on the rehydration capacity and color parameters of sliced pears (cv. Ankara). Drying trials were conducted at 55, 65, and 75 degrees C. Pre-treatment consisted of immersion of pear slices in a citric-acid solution or blanching in hot water. Pre-treatment was found to have a significant effect on both rehydration capacity and color, with higher temperatures and pre-treatment resulting in decreases in drying time and increases in rehydration capacity. Effective diffusivity values ranged between 1.12x10(-10) and 2.94x10(-10) m(2)/s. Blanched pear slices had the lowest E a values (15.51 kJ/mol), followed by the samples immersed in citric acid (28.03 kJ/mol) and the untreated samples (33.48 kJ/mol). The Midilli et al. model displayed the best fit to the drying data of five models tested based on the statistical criteria evaluated. Natural color of fresh pear was best preserved with lower drying temperatures and pre-treatment with citric acid.