Structure–process interaction in mass transfer processes: Application of ethanol and ultrasound in a vascular structure

摘要

This study aimed to evaluate the application of ultrasound and/or ethanol technologiesprior to convective drying in samples with a particular vascular structure (pineapplecore). Pineapple cores were cut in parallel (Lc) or perpendicularly (Tc) oriented tovascular bundles (VB). Effects on drying kinetics (50℃, 1.0 m/s), shrinkage, rehydrationkinetics (25℃), size recovery, and texture (50% uniaxial compression) were evaluated.Drying kinetics was fitted to Page model and rehydration kinetics to Pelegmodel. As main results, a reduction in drying time up to 60% was observed when thecombined pretreatment for 10 min was applied in Tc samples. Regarding shrinkage,the Tc samples better preserved their diameter (>53%), while the Lc samples betterpreserved their height (>73%) after drying, which was explained by the parallel orientationof the VB to each dimension. In addition, Tc samples showed higher rehydrationrate while the Lc samples showed greater water retention (～12 more). Afterrehydration, samples recovered their height and diameter by more than 70%. Furthermore,principal component analysis suggested that differences in shrinkage dueto VB orientation are very related to rehydration kinetics characteristics. Theseresults contribute to better explaining the technology–process–structure interaction.