DPPH radical scavenging activity
The free-radical scavenging activity of the extracts of rice fractions
were evaluated using the DPPH method (Table 2). The ability
to scavenge DPPH radical by rice fractions was in the order of
bran > husk > brown rice > milled rice for all samples. The DPPH
radical scavenging varied from 42.0% to 89.5% of husk, 37.5% to
68.0% of brown rice and 25.2% to 39% of milled fractions. The corresponding
values for the bran fraction were 85.9% to 86.7%. However,
the samples, especially those of husk fractions, from site 2
demonstrated the highest scavenging capacity (89.5%). The varied
radical scavenging activity of the extracts depended on the amount
of total phenolic in each fraction. This finding supports the data
previously reported in a study where the antioxidant activity was
dependent on the actual composition of milling fractions (Liyana-
Pathirana & Shahidi, 2007). In addition, all rice fractions (except
for milled rice) showed the ability to scavenge the DPPH radical
at a rate higher than BHT (0.2 mg/ml) but lower than ascorbic acid
with the concentration at 0.2 mg/ml and Trolox with the concentration
0.1 mM (Fig. 1).