Effect of water-extractable arabinoxylans from wheat aleurone and bran on lipid peroxidation and factors influencing their antioxidant capacity

•Arabinoxylans (AX) were extracted from wheat aleurone and bran.•AX chemical composition and structure was characterized.•Effect of AX on lipid peroxidation was demonstrated.•Antioxidant activity is influenced by the ferulic acid content of AX.

Dietary lipid hydroperoxides (LOOH) are implicated in the rise of colon cancers. We investigated the effect of water-extractable arabinoxylans (WEAX) on lipid peroxidation under simulated gastric conditions. Water-extractable fractions containing mostly arabinoxylans were isolated from wheat aleurone and wheat bran and fractionated by stepwise precipitation with (NH4)2SO4 at 50% and 75% saturation. LOOH concentration (121.2±3.8 µM/g) of grilled chicken breast muscle increased by 30%; however, it remained unaltered or decreased (≤35%) depending on type and concentration of WEAX fractions. Antioxidant capacity of WEAX fractions based on DPPH, ABTS and ORAC was 28.2 - 147.9, 91.2 - 355.3, and 185.9 - 527.5 µM TE/g, respectively. The content of ferulic acid residues in WEAX fractions (R =0.99) and relative proportions of monosubstituted xylose residues (R =0.80) influenced the antioxidant capacity. Consumption of diets rich in feruloylated WEAX may offer protection against oxidative damage in the gastrointestinal tract.