Rehydration kinetics of high-pressure pretreated and osmotically dehydrated pineapple.

Rehydration kinetics of high-pressure pretreated (100, 300, and 500 MPa for 10 min) and osmotically
dehydrated pineapple (Ananas comsus) cubes (2 × 2 × 1 cm) were studied at different temperatures (5, 25, and 35 °C),
and compared with ordinary osmotically dehydrated samples. The effective diffusion coefficients for water and
solute were determined, assuming the rehydration process to be governed by Fickian diffusion. Diffusion coefficients
for water absorption into the tissue as well as for solute diffusion out of the tissue were found to be lower in the
samples subjected to high-pressure treatment. Further, the diffusion coefficients decreased with increase in treatment
pressure. A possible explanation for the observed decrease in diffusion coefficients can be attributed to the
permeabilization of cell membranes, the release of cellular components, and structural changes of the cell materials.
The diffusion coefficients were correlated with rehydration temperature (T) and treatment pressure (P) by an Eq.
of the form D 5 A exp[2(B.P 1 C/T)], where A, B, and C are constants.