Cut orientation effect on mass transfer: Drying and rehydration of yellow sweet potato cylinders

Abstract

This work aimed to evaluate how cut orientation affects mass transfer during the drying and rehydration process. Sweet potato cylinders of 1.90 cm of diameter and 0.50 cm of height were prepared. Three cut orientations were carried out regarding the vascular tissue orientation, preparing longitudinal, transverse and oblique (45°) cuts. In addition, osmotic pretreatment (50°Brix sucrose solution) was also evaluated. Convective drying and rehydration kinetics were evaluated at a constant temperature. As results, cut orientation and osmotic pretreatment did not affect the drying kinetics. However, transverse cut without osmotic pretreatment presented less shrinkage than the other cut orientations. On the other hand, rehydration process was affected by cut orientation, being longitudinal cut the slowest sample absorbing water. In conclusion, both the cut orientation and osmotic dehydration did not show important effects on convective drying. Despite that, cut orientation affected shrinkage and rehydration kinetics of sweet potato cylinders.