PHENOLICS IN RICE: GENETIC VARIATION, CHEMICAL CHARACTERIZATION AND ANTIRADICAL EFFICIENCY

Authors: Goffman, Fernando; Bergman, Christine

Submitted to: American Association of Cereal Chemists Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 3/2/2002
Publication Date: 11/1/2002
Citation: GOFFMAN,F.D., BERGMAN,C.J., PHENOLICS IN RICE: GENETIC VARIATION, CHEMICAL CHARACTERIZATION AND ANTIRADICAL EFFICIENCY, AMERICAN ASSOCIATION OF CEREAL CHEMISTS MEETINGS,. p. 163.

Interpretive Summary:

Technical Abstract: Plant phenolics form an extensive group of compounds which prevent oxidation of lipids and may exert beneficial effects on human health. Several studies were carried out to characterize phenolics in rice. Three hundred twenty rice cultivars with varying bran color were grown in the same location and analyzed for total phenolic content. The purple and the red lines varied from 0.29 to 5.83 mg of gallic acid equivalent per g grain (mg GA eq./g), whereas the brown lines ranged from 0.25 to 2.86 mg GA eq./g. The light-colored lines were in the range of 0.23 to 0.62 mg GA eq./g. These results confirm our previous data which suggested that rice lines with darker bran may exhibit higher content and broader variation for total phenolics. In addition, phenolic extracts of a red (EAS 3) and a purple rice line (Tai Black), both with high total phenolics contents, were separated into low and high molecular phenolics (tannins) using Sephadex LH20. Low molecular phenolics accounted for 12.8 percent and 33 percent of the total phenolics content in EAS 3 and Tai Black, respectively, suggesting that tannins are the principal phenolics in high-phenolic rice lines. By analyzing methanolic extracts in another set of rice bran samples, a high correlation between antiradical efficiency and total phenolics was detected (r2= 0.99), indicating that phenolics play a major role in the free radical scavenging ability of rice bran extracts.