Characterization of Antioxidant Compounds and Antioxidant Activity of Indian Rice Varieties.

The present work is aimed at characterisation of phenolic acids and
rice bran oil (RBO) of Njavara, a medicinal red rice variety and
other rice varieties. The antioxidant activities of the rice polyphenols
were also studied by radical scavenging assay, reducing power and
microsomal lipid peroxidation. Pigmented rice varieties (Njavara
and Jyothi) had high antioxidant activities than non-pigmented
variety (IR 64). Acetone extracts showed higher phenol content and
antioxidant potency compared to methanol and ethanol extracts.
Njavara showed higher reducing capability and higher soluble
(15%–46%) and insoluble phenolic acids (51%–75%) compared
to Jyothi and IR 64. An array of phenolic acids were identified,
the major being ferulic and p-coumaric acid. The ferulic
acid concentration of Njavara in soluble and insoluble form was
33%-66% and 51%–75% higher, respectively, than non-medicinal
rice. Njavara RBO was a better source of tocopherols. However,
oryzanol composition of Njavara was similar to Jyothi and IR 64.