In the case of osmotically dehydrated cherries the total drying
time amounted to 374 min, but for cherries pretreated with ultrasounds it was only 330 min on average. As it follows from the graphs
in Fig. 2, the supply of cooler air into the chamber as well as the
osmotic dehydration affected the drying kinetics. Due to periodical
changes of air temperature it was managed to keep the samples
temperature at a safe level for a long time. The temperature curves
of the samples are slightly different for the tests presented in Fig. 2.
The biomaterials dehydrated by osmosis due to the sugar gain in
tissues were characterized by lower average temperature during
intermittent drying. The most efficient drying method for cherries
seems to be the third one (Fig. 2c), where the drying time was shortened by about 2 h, compared with that gained during air drying at
constant temperature (AD). Therefore, the combination of UDOD
and AD (5–30) significantly accelerated the moisture removal, and
what is important, giving at the same time a better quality of dried
material (Fig. 3).