Phenolic acids with antioxidant activity in maize bran and wheat bran

Soluble and bound phenolic acids were obtained from maize and wheat bran and the level of total phenols were determined (Folin-Ciocalteu), phenolic acids (HPLC), antioxidant activity (DPPH, ORAC) and the presence of diferulic acids (UV spectra). The concentrations of total phenols, ferulic acid, and coumaric acid ranged from 1 637 to 9 718 mu gEAF g(-1), from 12 to 4 527 mu g g(-1) and from 7 to 664 mu g g(-1), while the antioxidant activity had 9.52 to 64.14 % of DPPH inhibition and from 11.46 to 67.09 mu molET g(-1) in ORAC. The presence of the diferulic acids 8-8', 8-5', 5-5' and 8-O-4' was identified in the bound fractions. All fractions presented significant levels of total phenols, phenolic acids and antioxidant activity, the bound fraction of maize bran being the one that presented the highest concentrations.