OPTIMIZATION OF VEGETAL PEAR DRYING USING RESPONSE SURFACE METHODOLOGY

The aim of this work was to optimize the drying process of vegetal pear, and minimize energy resources (cost) under pre-fixed limits involving vegetal pear moisture, color and productivity. The optimization of vegetal pear drying was made by using Response Surface Methodology (RSM) for minimum process cost and color difference between fresh and dried samples (moisture ≤0.10 g water g d.m.^-1). A pilot plant drier was used for dehydrating vegetal pear slices (0.5 cm of thickness). The tests were carried out at different air temperature (60 to 70 °C), samples diameter (4 to 7 cm) and pre-treatment with ascorbic acid solutions (0 to 0.1 % w/w). The optimum conditions of drying process were 63 °C, 5 cm of sample diameter, and 0.075 % of ascorbic acid concentration. On the optimized drying conditions, dried vegetal pear presented values of moisture content of 0.052 g water g d.m.^-1, color difference 11.65, production 0.0073 kg h^-1 and total cost 30.58 $ kg dried product^-1.