Isolation of arabinoxylan and cellulose-rich arabinoxylan from wheat bran of different varieties and their functionalities

Abstract

The study evaluated the yield, emulsifying, antioxidant properties, protein content and amino acid composition of water-extractable (WE) and alkali-extractable (AE) Hemi-B and the water holding capacity and protein content of cellulose-rich arabinoxylan (CAX) fractions isolated from the bran of four wheat varieties. It was observed that CAX from the variety C-306 possessed the lowest protein content (3.83%) and the highest water holding capacity (16.13%). Total phenolic content of AE-Hemi-B and WE-Hemi-B fractions varied from 4.54 to 7.47 mg ferulic acid equivalents (FAE)/g and 3.51–4.91 mg FAE/g, respectively. Except for the AE-Hemi-B fraction of HS-490, bound phenolic content was higher than free phenolic content. AE-Hemi-B had exceptionally higher bound phenolic and antioxidant content. FTIR bands at 1364 cm−1, 1028 cm−1 and 849 cm−1confirmed the presence of a highly branched arabinoxylan structure. The presence of phenolic ring structure, characteristic of ferulic acid, was confirmed by the band signal at 1520 cm−1. The emulsion stability of WE-Hemi-B decreased drastically, after storage at accelerated temperature (60 °C). However, all AE-Hemi-B yielded good emulsions, expect HD-2967 variety, which exhibited the poorest emulsion stability, while, C-306 yielded exceptionally stable emulsion, better than well-known corn fiber gum, up to 3 days under accelerated storage.