The BR and PGBR of Khao dok mali variety 105 are rich sources
of c-oryzanol and tocols compared to WR, indicating health promoting
benefits. In addition, pre-germination and parboiling processes
increased those bioactive substances. The experiment
demonstrated the effect of cooking methods on c-oryzanol and
tocols. Furthermore, the steaming method is the best cooking process
for preserving the important health benefitting compounds
compared with frying and boiling. Steaming protected the bioactive
compounds with the increase in extraction and viscosity.
Boiling enhanced the leaching of bioactive compounds, and frying
degraded the bioactive compounds through high temperature. This
study can help to establish guidelines for cooking methods for rice
and to provide recommendations to consumers. The information
from this study provides a motive for the government to support
the consumption of BR and PGBR. Furthermore, the use of microscopy
is useful, and it should be used along with biochemical analysis
to elucidate the relationship between tocols and c-oryzanol
and the rice matrix.