Studies on the effects of microwave drying and cabinet tray drying on the chemical composition of volatile oils of garlic powders

Garlic cloves in the form of bits were dried in a
cabinet tray dryer and a microwave dryer, and pulverized to
obtain free flowing powder. The volatile oil was obtained
by hydro-steam distillation method. Fresh cloves and the
powders resulting from the two drying methods were used
for obtaining the volatile oil, which was analyzed by GCMS.
The studies were mainly restricted to comparing the
effect of drying methods on the volatile oil composition
of the powders. Although the drying time was reduced
considerably from 8 h in a cabinet dryer to 0.25 h in a
microwave dryer, essential oil yield and color values were
lower, and flavor quality varied considerably. The relative
concentrations of major peaks such as diallyl disulfide, diallyl
tetrasulfide increased in both the drying methods, and
it was more so in microwave-dried samples. However, the
concentrations of the other two major peaks, diallyl trisul-
fide and allyl methyl trisulfide, decreased in both drying
methods, and they were lower in microwave-dried samples.
Hunter values of L and b were lower for samples obtained
by microwave drying as compared to those of cabinet-dried
samples.