Effect of microwave drying on the phytochemical composition of volatiles of ginger.

The influence of drying methods on the volatile components of Zingiber officinale rhizomes was studied. The
drying methods employed were convection (CD) and microwave (MW) drying. The drying time reduced
significantly from 720 min in case of CD to 25–48 min in MW drying depending on the microwave power
level (PL 100, 80, 60 and 40 correspond to 800, 660, 525 and 385W, respectively). The MW-dried (PL100,
800W) sample retained the maximum volatile fraction (3% v ⁄ w). Seventy-four constituents accounting for
more than 99% of the essential oil from fresh ginger were identified. The concentration of major compound
(zingiberene), in essential oils, was marginally increased (7%) in MW dried (PL100), whereas it was
decreased not only in CD (43%) but also at other MWPLs employed in drying (25–49%). Hence, it could be
concluded thatMWsubstantially reduced the drying time and the sample dried at PL 100 retained maximum
quantity of volatiles.