(Fig. 5). Frying increased the total tocols content, especially
a-tocopherol, which came from the oil used because there was no
a-tocopherol detected in raw PGBR and BR. The fresh soybean oil
used in the experiment was analysed, and a-tocopherol was identified
(6–8 mg/100 g). In addition, trace amounts of a-tocopherol
was also found. Boiling method did not significantly degrade the
tocols as c-oryzanol and the tocols have different heat stabilities
and chemical structures. Hence, the decreasing trend of
c-oryzanol and tocols content were different.
In case of comparison between c-oryzanol and tocols as
affected by steaming, frying and boiling methods, the tocols were
less affected by all cooking methods. Steaming minimised the loss
of c-oryzanol and tocols. Frying process increased the tocols content
depending on the type of oil used.