The variations of hardness during o

The variations of hardness during osmotic
dehydration of red pitayas using different sucrose
concentrations were presented in Figure 8. It is clear
that osmosed samples were considerably softer than
untreated samples and as sucrose concentration and
time increased the hardness of the samples decreased
gradually. This was explained by substantial changes
in cellular tissues including loss of cell turgor
(plasmolysis), filling of air spaces with hypertonic
solution and degradation of the middle lamellae
during osmosis of fruits and vegetables (Lewicki and
Lukaszuk, 2000). Similar observations were reported
by Lewicki and Lukaszuk (2000), Chirlat and Talens
(2005) and Katsiferis et al. (2008) and Castello et
al. (2010) working on apples, orange, Granny Smith
apple slices and strawberries.