Emerging Technologies for Food Processing, 2nd Edition

11.2. Mechanism of Osmotic Dehydration

In the mechanism reported earlier, it was proposed that during osmotic dehydration, a superficial layer 2–3 mm deep forms in the product, which has a major effect on mass transfer favoring water loss, although limiting solute deposition and reducing the loss of water-soluble solutes (Raoult-Wack et al., 1991; Marcotte and Le Maguer, 1992). Azuara et al. (2009) also demonstrated that after 1 h of osmotic dehydration of apple, the outer layer of the apple sample lost water and gained sucrose, the extent of which subsequently decreased toward the internal layers. A fine layer of greatly dehydrated cells was formed on the surface around the sample, which determined the mass transfer rate in the whole tissue. ...