Drying rates were calculated for each of the three modes
of operation. All three modes exhibited a constant drying
rate period and a decreasing drying rate period. A significant
difference was observed between the hybrid mode
and the solar and LPG modes; the slowest drying rate
(0.022 kg water/kg d.s. min) occurred in solar mode, due
to the low temperature reached during the process. In contrast,
drying rates for GHS and HHS exhibited similar constant
drying rate periods, at 0.032 and 0.030 kg water/kg
d.s. min, respectively. These rates remained constant until
50% (w.b.) of the moisture in the foodstuff had been dried.
After 50% had been reached, drying rates decreased for
both modes at the same rate of change, until reaching a
final moisture level in the foodstuff of 10 ± 0.02%.