Structural features of arabinoxylans from sorghum having good roti-making quality

Arabinoxylans (AX) from an Indian variety of sorghum (M354) having good roti(Indian flat bread)-making quality were isolated with barium hydroxide and 10% sodium hydroxide (Hemicellulose B). Arabinoxylans from both fractions were further purified by alcohol precipitation at acidic pH and glucoamylase digestion. Structural features of the purified arabinoxylans were studied by a combination of methylation analysis involving GC–MS, 13C NMR, oxidation studies and FT-IR spectroscopy. The results indicated a xylan backbone in β-1,4 linkage, which is occasionally branched at O-3 or at O-2 and O-3. The branches contained arabinosyl residues in furanose form, linked mainly by α-1,3. Fully branched arabinosyl residues were also present.