Rehydration Capacity and Kinetics of Solar-Dried Carrot (Daucus carota) Slices as Affected by Blanching and Osmotic Pretreatments

Abstract

Abstract This study investigated effects of pretreatments on rehydration characteristics of solar-dried carrot slices. Blanching at 55, 65 and 75°C for 45 minutes and osmotic dewatering in 5%, 10% and 15% salt solutions for 5 h were used as pretreatments. Rehydration capacity of the dried carrots was determined by soaking 20 g sample in hot water at 95°C for 10 min and rehydration kinetics was carried out by soaking 5 g samples at 75, 85 and 95°C. All the treatment conditions separately and in combination influenced the rehydration characteristics of the carrot slices. High values of rehydration capacity and low lixiviated soluble solids, which indicates better quality, were obtained for samples treated at the lower blanching temperature. Similarly the lower salt concentration resulted in higher rehydration capacity and lower lixiviated soluble solids. The interaction of the lower level of both pretreatments produced higher rehydration capacity and lower soluble solid losses. A first-order kinetic model was used to describe the rehydration kinetics. A better rehydration performance was observed for the samples subjected to the lower levels of pretreatments and rehydration conditions.