Corn bran fiber valorization via feruloylated xylooligosaccharide production: Evaluation of antioxidant and α-amylase and α-glucosidase inhibitory effects.

Feruloylated xylooligosaccharides (FXOS) were alkali-solubilized from corn bran followed by enzymatic treatments (4 enzyme treatments were compared). The FXOS were ultrafiltrated using molecular weight cut-offs of 1 kDa and 10 kDa. Antioxidant activities, α-amylase and α-glucosidase inhibitory effects were assessed for the different fractions. The lower molecular weight fraction (<1 kDa), enzymatically hydrolyzed for 24 h (FXOS1-24), exhibited the strongest in vitro antioxidant activity, with IC50 values of 0.14 mg/mL (DPPH) and 1.0 mg/mL (ABTS•+). In addition, FXOS1-24 inhibited porcine pancreatic α-amylase (IC50 ∼ 13 mg/mL) and showed significant α-glucosidase inhibitory activity, suggesting potential antidiabetic properties. The bioactivities correlated positively to ferulic acid content of the solubilized xylooligosaccharides. The findings demonstrate new functional effects of soluble feruloylated xylooligosaccharides that yield new opportunities for upgrading of corn bran from corn starch processing.