3.3. Effect of different cooking methods on tocols and c-oryzanol
After WR, BR and PGBR were subjected to different thermal
cooking, there was a reducing trend of c-oryzanol in both the BR
and PGBR (Fig. 3A). The c-oryzanol content in case of steam cooking
samples was highest, followed by boiling and frying based
samples.
In addition, the reduction trend was similar between PGBR and
BR (steaming > boiling > frying), which indicated the same degree
of degradation of c-oryzanol. After boiling, the germ was removed;
however, the concentration of c-oryzanol was only slightly
decreased, indicating that the germ did not significantly contribute
to the c-oryzanol content in rice. In general, the rice starch gelatinisation
starts at 68 C and is completed at 78 C (Stephen, 1995),
which means that in this experiment, the starch was completely
gelatinised as the cooking temperature reached 100 C. In addition,