Modeling mass transfer during osmotic dehydration of different vegetable structures under vacuum conditions

Abstract

Osmotic dehydration (OD) is a method to partially reduce moisture of food, aiming to improve the shelf life and the stability of the products. The mass transfer that occurs during this process can be enhanced with the application of reduced pressure in the first minutes of the osmotic dehydration (pulsed vacuum osmotic dehydration - PVOD). The present work aimed to study the vacuum effect on the kinetics of osmotic dehydration of vegetables (carrot, eggplant and beetroot) in terms of water loss, solids gain and water activity, in ternary solution. Moreover, mathematical modeling of experimental data obtained from the osmotic processes, was employed for correlating the mass transfer of the food product under the different conditions. An intensification of mass transfer was observed for carrot and eggplant in the vacuum treatments. This was related to their porous structure. The present work demonstrated a lack of fit of Fick’s second law for describing the dehydration kinetics of the eggplant.