Hemicellulose

A hemicellulose can be any of several heteropolymers (matrix polysaccharides) present in almost all plant cell walls along with cellulose. A heteropolymer or copolymer is a Polymer derived from two (or more Monomeric species as opposed to a Homopolymer where only one monomer is Cellulose is an Organic compound with the formula, a Polysaccharide consisting of a linear chain of several hundred to over ten thousand β(1→4 While cellulose is crystalline, strong, and resistant to hydrolysis, hemicellulose has a random, amorphous structure with little strength. Hydrolysis is a Chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions which may go on to participate in further reactions It is easily hydrolyzed by dilute acid or base as well as myriad hemicellulase enzymes.

1 Composition
2 Structural comparison to cellulose
3 Native structure
4 Applications
5 See also

Composition

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. Xylose or wood sugar is an Aldopentose &mdash a Monosaccharide containing five Carbon Atoms and including an Aldehyde Functional Mannose is a Sugar Monomer of the Hexose series of Carbohydrates Metabolism Mannose enters the carbohydrate Metabolism Galactose (Gal (also called brain sugar) is a type of Sugar which is less sweet than Glucose. Rhamnose is a naturally occurring Deoxy sugar. It can be classified either as a methyl- Pentose or a 6-deoxy- Hexose. Arabinose is an Aldopentose &mdash a Monosaccharide containing five Carbon Atoms and including an Aldehyde (CHO Functional Hemicelluloses contain most of the D-pentose sugars, and occasionally small amounts of L-sugars as well. A pentose is a Monosaccharide with five Carbon Atoms They either have an Aldehyde Functional group in position 1 ( aldopentoses Xylose is always the sugar monomer present in the largest amount, but mannuronic acid and galacturonic acid also tend to be present. Xylose or wood sugar is an Aldopentose &mdash a Monosaccharide containing five Carbon Atoms and including an Aldehyde Functional Mannose is a Sugar Monomer of the Hexose series of Carbohydrates Metabolism Mannose enters the carbohydrate Metabolism D-Galacturonic acid is a sugar acid an oxidized form of D-galactose.

Structural 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.

Native structure

Hemicelluloses are embedded in the cell walls of plants, sometimes in chains that form a 'ground' - they bind with pectin to cellulose to form a network of cross-linked fibres. In Biology, matrix (plural matrices) is the material between animal or plant cells, the material (or tissue in which more specialized structures are embedded Pectin (from Greek πηκτικός - pektikos, "congealed curdled" a white to light brown powder is a Heteropolysaccharide

Applications

As percent content of hemicellulose increases in animal feed the voluntary feed intake decreases.

Hemicelluloses include xylan, glucuronoxylan, arabinoxylan, glucomannan, and xyloglucan. Xylan is a generic term used to describe a wide variety of highly complex Polysaccharides that are found in plant cell walls and some Algae. Glucomannan is a water-soluble Polysaccharide that is considered a Dietary fiber. Xyloglucan is the main Hemicellulose in the primary Cell wall of dicotyledonous plants and occurs in the cell walls of all vascular plants

Hemicellulose is represented by the difference between Neutral Detergent Fiber (NDF) and acid detergent fiber (ADF). Neutral Detergent Fiber (NDF is the most common measure of fiber used for Animal feed analysis but it does not represent a unique class of chemical compounds

Dictionary

-noun

(chemistry) a mixture of several plant polysaccharides, of smaller molecular weight than cellulose, that are soluble in dilute alkali; they are involved in the manufacture of paper, and are used in the production of furfural and ethanol

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