Effect of Temperature on Okra (Abelmoschusesculentus) Fruit Slices Dehydrated Using a RefractanceWindowTM Dryer

Abstract

This paper presents the effect of temperature on the drying kinetics of the okra fruit slices using a Refractance WindowTM dryer. Okra fruit slices, 3 mm thick were dried at three temperatures. The slices were dehydrated at separate times at temperatures of 75oC, 85oC, and 95oC. Themoisture content of the slices was determined periodically during the drying process. The experimental data obtained were fitted tothin-layerdrying models commonly used in the dehydration kinetics of fruit and vegetables. Observations indicated that the slices dried to a moisture content below 0.11 g-water/g-solid (dry basis) in about 90 - 110 minutes for the process conditions studied. For the nine models considered, the regression results suggested that the Haghi and Ghanadzadeh thin-layer model best describes the drying kinetics for the 3 mm thick slices for the temperatures 75oC, 85oC, and 95oC; the coefficient of determination (R2) values were 0.9992, 9973, 9993 for the respectively. The benefit of the work done here will aid in understanding the design, analysis, and optimization of the Refractance WindowTM equipment in the drying of food