A hemicellulose can be any of several
heteropolymers (matrix polysaccharides) present in almost all plant cell walls along with cellulose. While cellulose is crystalline, strong, and resistant to hydrolysis, hemicellulose has a random, amorphous structure with little strength. It is easily hydrolyzed by dilute acid or base as well as myriad hemicellulase enzymes.
Hemicellulose contains many different sugar monomers. In contrast, cellulose contains only anhydrous glucose. For instance, besides glucose, sugar monomers in hemicellulose can include
xylose, mannose, galactose, rhamnose, and arabinose. Hemicelluloses contain most of the D- pentosesugars, and occasionally small amounts of L-sugars as well. Xyloseis always the sugar monomer present in the largest amount, but mannuronic acid and galacturonic acidalso tend to be present.
tructural comparison to cellulose
Unlike cellulose, hemicellulose (also a polysaccharide) consists of shorter chains - 500-3000 sugar units as opposed to 7,000 - 15,000 glucose molecules per polymer seen in cellulose. In addition, hemicellulose is a branched polymer, while cellulose is unbranched.
Hemicelluloses are embedded in the cell walls of plants, sometimes in chains that form a 'ground' - they bind with
pectinto cellulose to form a network of cross-linked fibres.
As percent content of hemicellulose increases in animal feed the voluntary feed intake decreases.
xylan, glucuronoxylan, arabinoxylan, glucomannan, and xyloglucan.
Hemicellulose is represented by the difference between
neutral detergent fiber(NDF) and acid detergent fiber (ADF).
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