Because branches in the xylans start with Ara or glucuronic acid, which were not detected in IOS, the XOS are apparently the fragments of the xylan backbone that consists of a linear chain of β-1,4-linked xylopyranose residues.
The backbone is a linear chain of 1,4-linked mannose residues to which galactose residues are 1,6-linked at every second mannose, forming short side branches [43].
Pectins consist of compounds made up of a backbone of linear (1,4 -linked α-D-galacturonan and side chains mainly of α-D-galactopyranose, α-L-arabinofuranose and α -(1,4 -linked rhamnopyranosyl residue [ 5, 16– 18].
Xylan is a major polysaccharide of hemicellulose from agricultural residues and hardwoods, consisting of a linear backbone of β-D-xylopyranosyl residues linked by β-1,4-glycosidic bonds.
Glucuronoxylans consist of a linear backbone of 1,4-linked β- d-xylopyranosyl units that are substituted with acetyl and 4- O-methylglucuronic acid side chains.
Xylan, the main hemicellulose in hardwoods and annual plants, consists of a linear backbone of β-1,4-linked xylopyranose (Xyl) residues.
Xylans in hardwoods and annual plants consist of a linear backbone of β-(1→4 -D-xylopyranosyl residues, substituted by α-L-arabinofuranosyl units in the positions of 2- O- and/or 3- O-, by 4- O-methyl-glucopyranosyl uronic acid in the position of 2- O, and/or by acetyl groups in the positions of 2- O and/or 3- O [ 1→4 -D-xylopyranosyl
Xylans in annual plants consist of a linear backbone of β-(1 → 4 -D-xylopyranosyl residues, substituted by α-L-arabinofuranosyl units in the positions of 2-O and/or 3-O, by 4 -D-xylopyranosylranosyl uronic acid in the position of 2-O, and/or by acetyl groups in 2-O and/or 3-O [ 6].
Xylans, the main hemicelluloses in hardwoods and annual plants, consist of a linear backbone of β-(1→4 -D-xylopyranosyl residues, substituted by α-L-arabinofuranosyl units in the positions of 2- O and/or 3- O, by 4- O-methyl-glucopyranosyl uronic acid in the position of 2- O, and/or by acetyl groups in the positions of 2- O and/or 3- O [ 1→4 -D-xylopyranosyl
It is composed of a linear tetrasaccharide backbone made of three L-rhamnose residues, A, B, and C, and a N-acetyl-D-glucosamine residue D, that is common to all S. flexneri, except serotype 6, and of an α-D-glucose residue E, branched at position 4 of rhamnose C that specifies serotype 2a [22], [22].
