The Structure of Xanthan Gum

 The Structure of Xanthan Gum

 

Molecular Formula: (C35H49O29)n

CAS Number: 11138-66-2

Xanthan gum was discovered in the 1950s at the NRRL Northern Regional Research Laboratories of United States Department of Agriculture. It is a kind of neutral water-soluble polysaccharide secreted from the Xanthomonas campestris.

The molecules of xanthan gum consist of D-glucose, D-mannose, D-glucuronic acid, acetyl and pyruvic acid. Its relative molecular mass ranges from 2×106 to 5×107. The primary structure consists of glucosyl main chain by β—(1→4) bond and trisaccharide side chain. Its side bond is alternately connected by D-mannose and D-glucuronic acid. The molecular proportion is 2:1. The trisaccharide side chain is connected to the main chain by α—(1→3) bond of D-mannose with acety in C6 band of position. The higher-order structures are helixes and multiple helixes formed by hydrogen bond maintaining the structures between the side chain and the main chain.

The secondary structure is a rod-like double helix structure in which the side chain is reversely wrapped on the main chain skeleton and hydrogen bond plays an important role in maintaining the structures. The tertiary structure is a spiral complex formed by the combination of weak non-covalent bonds in the rod-like double helix structure. At the end of side chain, there exists pyruvic acid in the form of acetals in D-mannose residues 

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On December 12th, 2012, posted in: Products and Techniques, xanthan gum by Tags:

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