Maize bran gum: Extraction, characterization and functional properties

A water-soluble maize bran gum (MBG) was alkali-extracted under mild conditions from maize bran. MBG presented an arabinoxylan (AX) content of 74% (w/w), a ferulic acid content of 0.34 μg/mg MBG, an A/X ratio of 0.85 and an intrinsic viscosity of 208 ml/g. Gelling and emulsifying capabilities of MBG at different concentrations were investigated. Gels were obtained from this MBG by laccase covalent cross-linking of ferulic acid leading to the formation of diferulic (di-FA) and triferulic (tri-FA) acid. Gel hardness increased from 0.32 to 0.81 N as the MBG concentration changed from 1 to 2% (w/v) while the di-FA and tri-FA contents remained constant (0.030 and 0.015 μg/mg MBG, respectively). The emulsion stability index (ESI) of oil-in-water containing different MBG concentrations was also investigated. ESI ranged from 0.01 to 0.20 as the MBG content in the mixture increased from 0% to 1% (w/v).