Structural variations of arabinoxylans extracted from different wheat (Triticum aestivum) cultivars in relation to chapati-quality

• Structural features of arabinoxylans from four wheat varieties were elucidated by combination of methods.
• Arabinoxylans consisted of a xylan backbone in which xylose residues are linked by β-(1–4) linkages.
• Xylan backbone is substituted at O-3 or at O-2 and O-3 by arabinose residues.
• Arabinoxylans were highly branched coupled with higher amounts of ferulic acid in good wheat varieties.
• Variations in the structural features of arabinoxylans were observed in different wheat cultivars.

Wheat varieties, such as DWR-162, GW-322 (good chapati making quality) and MACS-2496, HD-2189 (poor chapati making quality) were used to study the structural features of arabinoxylans. Structural features of the purified arabinoxylans were elucidated by a combination of methods such as methylation analysis, 13C-NMR, FT-IR, periodate oxidation, Smith degradation and optical rotation measurements. The results indicated a xylan backbone in β-(1–4) linkage, which is substituted at O-3 or at O-2 and O-3. Completely branched xylosyl residues were also observed in these wheat arabinoxylans. The wheat varieties known for good chapati making quality (DWR-162 and GW-322) revealed arabinoxylans with higher degree of branching pattern compared to those of poor wheat varieties such as MACS-2496 and HD-2189. Variations in the structural characteristics of arabinoxylans such as degree of branching pattern coupled with ferulic acid contents are of interest in wheat varieties differing in chapati making quality.

Proposed structural variations of arabinoxylans in good (A) and poor wheat varieties (B) for chapati quality.Figure optionsDownload as PowerPoint slide