Convective Hot-air Drying of Green Mango: Influence of Hot Water Blanching and Chemical Pretreatments on Drying Kinetics and Physicochemical Properties of Dried Product

Abstract

ABSTRACT Currently, there is a growing market demand for dehydrated green mango powder for the development of value-added products. Preservation of green mangoes through drying is a good option. In this study, the influence of pretreatments and drying temperatures on drying kinetics and physicochemical properties of dried product was investigated. The sliced (4 mm thickness) green mango samples were pretreated with hot water blanching at 98°C for 3 min, 3% (w/v) ascorbic acid, and 3% (w/v) calcium chloride solutions for 1 h at room temperature (30°C). The pretreated and untreated samples were dried at 50, 60, and 70°C with an air velocity of 2.25 m/s. The dried products were ground to powder and evaluated physicochemical quality in terms of bulk and tapped density, flowability, water solubility index, rehydration capacity, total soluble solids, pH and ascorbic acid. It was observed that the moisture removal rate increased while increasing the drying temperature, and pretreated (blanching) samples dried faster than untreated samples. The experimental data were fitted to four models and evaluated for their ability to describe the drying behavior and predict the drying kinetics, of which the Logarithmic model was found to be the best. Effective moisture diffusivity and activation energy were estimated using Fick’s second law of moisture diffusion and the Arrhenius-type equation, respectively, and corresponding values were 1.209 × 10−7 to 1.566 × 10−7 m2/s and 43.873 to 44.403 kJ/mol. The samples treated with blanching and ascorbic acid showed higher physical properties and ascorbic acid content, respectively.