It is interesting to note that alpha-turmerone, a major component
in the essential oil (20.5%) and ethanol oleoresin (53.4%) from
fresh rhizome is only a very minor one in the essential oil (0.6%)
and oleoresin (6.5%) of the dry rhizome. Also, the content of
beta-turmerone in dry rhizome (4.3% in essential oil as well as
oleoresin) is less than a half of the amount found in green rhizomes
(11.1% in essential oil and 18.1% in the oleoresin). In dry rhizome,
comparatively less percentage of alpha- and beta-turmerone may
be probably due to, absence of aromatic ring and presence of two
conjugated double bonds which may undergo oxidation/polymerization
very easily.