Glucomannans, methylation analysis

Hardwood hemicelluloses are represented by xylans and a small proportion of glucomannans. Hardwood xylans are linear polymers, constituted of [l,4]-linked xylanopyranosyl units that constitute the main skeleton. Every tenth D-xylanopyranosyl unit is substituted by a 4-0-methyl-D-glucuronic acid residue, linked to the birch xylan chain by [1,2] linkages, that has been found to retard the alkaline peeling reaction. Analysis of partially hydrolyzed xylan indicates that 4-0-methyl-D-glucuronic acid units linked to the C2 position are randomly distributed along the birch xylan backbone [9]. 

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