Pilot-scale isolation of glucuronoarabinoxylans from wheat bran

The major dietary-fiber component of wheat bran, glucuronoarabinoxylans, have been isolated from purified wheat bran in a pilot-scale procedure. Wheat bran, milled from the wheat variety Bussard, was purified with boiling 70% ethanol following removal of water-extractable arabinoxylans by extraction with water. Glucuronoarabinoxylans were subsequently extracted with 2% hydrogen peroxide of pH 11 at 40 °C. Residual proteins and mixed linked (1-3)(1-4)-β-d-glucans were removed enzymatically. The final product was precipitated with ethanol and had a purity of 70-80%. X/A-ratio was 1.25, ferulic acid content was below 0.1%, HPSEC analysis with LALS detection showed a single peak with an apparent MW of 100-110 kDa. 13C-NMR analysis showed the presence of mono- and di-substituted xylose residues of the xylan core. The procedure allowed the production of 350 g of glucuronoarabinoxylans within 1 week, using low priced chemicals of low toxicity. It can be easily upscaled to industrial scale.