The moisture ratio of grapes was affected by drying methods.
The hot air cabinet alone as a drying method required more
time to dry grapes. The drying rate curves indicated the absence
of a constant-rate drying period in all drying methods.
No benefits were seen when increasing drying time from 30
to 120 min when grapes drying started in hot air cabinet dryer
and finished in microwave oven for 1 min at any power level.
The hot air cabinet alone as a drying method had higher drying
constant ‘k’ compared to other two methods. The microwave
oven followed by hot air cabinet dryer as a drying
method achieved 78% of the optimum selection percentage.
However, the optimum drying method in the current study
has a selection percentage of 100%.