Extraction and characterisation of hemicelluloses from maize stem

– Extraction and characterisation of hemicelluloses are very important for converting them into functional materials and chemicals. Objective – To develop a method for isolation of hemicelluloses from all cell walls. Methodology – Sequential steps using 90% dioxane, 80% acidic dioxane, 100% dimethyl sulphoxide and 8% NaOH were used for extraction of the hemicellulosic preparations (H 1 , H 2 , H 3 and H 4 ) from maize stem. Advanced NMR techniques were used for the analysis of native hemicelluloses. Results – Hemicelluloses with high yieldd were isolated from all cell walls, and contained arabinoxylan as the major polysaccharide. H 3 was substituted by α ‐ l ‐arabinofuranose, α ‐ d ‐xylopyranose, and acetyl groups (degree of saturation = 0.12/0.09) at O ‐3/ O ‐2 of xylan. H 4 had a long continuous side chain of arabinose residues, and associated closely with non‐cellulosic glucose. The hemicelluloses formed more linkages with guaiacyl lignins, and some p ‐coumaric acids built a bridge between hemicelluloses and lignin in maize stem. Conclusion – This modified method is successful for the isolation of hemicelluloses with high yields from all cell walls of maize stem. Copyright © 2010 John Wiley & Sons, Ltd.