Assessment of oleoresin and gingerol contents in gamma irradiated ginger rhizomes.

Oleoresin and gingerol contents in gamma irradiated dried ginger rhizomes were evaluated to determine the effect of radiation and storage on these constituents of ginger. Dried ginger rhizomes were subjected to 0, 5 and 10 kilogray (kGy) doses of gamma rays from 60Co source. The oleoresin and gingerol contents were monitored for 9 months. Radiation treatment (10 kGy) reduced the decrease of the oleoresin content of ginger during the storage period by 14% in unground samples and 11% in ground samples. There was a dose-dependent decrease in the 6-gingerol content of the ground ginger decreased by 65.6, 67.4 and 70.4% for the 0, 5, and 10 kGy samples, respectively, while the corresponding values for the ungrounded ginger samples were 37.8, 40.0 and 44.3% at the end of the storage period.