Arabino glucuronoxylan and glucurono arabinoxylan

AGX are also the dominant hemicelluloses in the cell walls of hgnified supporting tissues of grasses and cereals. They were isolated from sisal, corncobs and the straw from various wheat species [4]. A more recent study on corncob xylans [30] showed the presence of a hnear, water-insoluble polymer 

In contrast to AGX, the GAX consists of an arabinoxylan backbone, which contains about ten times fewer uronic acid side chains than a-L-Ara/ ones, and has some Xylp residues doubly substituted with these sugars. GAX are located in the non-endospermic tissues of cereal grains such as in wheat, corn, and rice bran. The degree and pattern of substitution of GAX appears to vary with the source from which they are extracted. These differences are reflected in the ratio of Ara to Xyl, the content of MeGlcA, and the presence 

A recent study on wheat bran GAX [34] revealed the presence of lowly and highly substituted GAX fractions, which greatly differ in the amount and type of substitution by the Ara/ imits, but not in the content of the glucuronic acid, half of which occurs as the 4-0-methyl ether. Feruloylated GAX fractions were isolated from wheat bran by cold water, steam and dilute alkah [35]. The yields of water and steam-extracted material were 1.5 and 20-31%, respectively, however, they contained 1.5% and 19-28%, respectively, of GAX. The alkah extraction yielded 10-30% material containing more than 90% of the GAX with moderate FA content. 

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