Investigators
explained that this was due to rehydration, along with the release
of phenols from the cell walls and an increase in free hydroxyphenols.
Dewanto, Wu, Adom, and Liu (2002) reported that high temperature
applications, such as 88 C, to tomatoes did not affect
their phenolic content. The same group indicated that the thermal
process at 88 C deactivated oxidative and hydrolytic enzymes that
may cause the loss of phenolic acids. Chan et al. (2009) reported
that there was a decrease in TPC when leaves of ginger were dried
by the sun, in an oven, and by microwaves. The same group found
an increase in phenolic content in ginger leaves that had been
freeze dried. However, results were not calculated on the basis of
dried samples.