Rehydration Characteristics of Beetroot, Sweet Potato and Yam Slices Dried using the Refractance WindowTM Method

Abstract

This study presents four models' suitability for the rehydration ratio and moisture content history data during the hydration process of beetroot, sweet potato, and yam. The models are the Akinola et al., the Exponential, the Peleg, and the Weibull models. Rehydration occurred at 27◦C for the dehydrated sample slices, which had original dimensions of 25 mm × 25 mm × 3.0 mm. During rehydration, the mass/moisture content history data was recorded for the samples. Regression analysis established that the Akinola et al. Model best fit the rehydration ratio/ mixture content changes vs time history data. The study results show a rapid increase in rehydration in the initial hour of the rehydration process. This increase gradually decreases to a contact equilibrium value. For the yam, sweet potato, and beetroot slices, the rehydration ratio values approached 2.1, 2.1 and 6.5, respectively. This study provides a better understanding of the beetroot, sweet potato, and yam slices' rehydration process. Also, knowledge of the rehydration characteristics of the agro-products will be valuable in the design, operation and optimisation of processing equipment and prediction of water absorption with time.