Glucomannans structures

In describing and interpreting some of the more important properties of plant galactomannans, comparisons will be made with structurally similar polysaccharides, including the closely related glucomannans and galactoglucomannans, and those based on (1 — 4)-/3-D-xylan main-chains (for example, the arabinoxylans) and (1 — 4)-/3-D-glucan main-chains [for example, the amyloids and sodium 0-(carboxymethyl)cellulose]. 

Similar structural problems exist for the distribution of side chains in galactoglucomannans, xyloglucans, arabinoxylans, and 4-0-methylglucuronoxylans, and even for the distribution of acetyl groups in glucomannans and for related features in many other polysaccharides. 

The linear, but highly branched, molecular structure of the galactomannans is the reason for some specific properties which are quite different from those of the unbranched cellulose-like and water-insoluble mannans and glucomannans. Galactomannans are hydrated in cold water and give stable solutions even in acidic formulas. The interactions of galactomannans with other polysaccharides are the base of a variety of industrial applications. 

D-Glucomannans have a D-glucose D-mannose ratio ranging from 1 3 (salep) to 2 3 (konjac), and this appears to be a constant for a particular species. The establishment of the structure of glucomannan as a polymer... 

The cell wall of fungi is a complex, multilayered structure formed by at least two major polysaccharides. These major polysaccharides have been used as a taxonomic criterion for fungi, as some of them contain chitin-glucans, and others, glucomannans.123... 

Mannans and glucomannans from plant sources all contain linear chains of (1 —> 4)-linked d-D-mannose and /J-D-glucose residues as their main structural features. The only true mannans (that is, polysaccharides containing 95% or more of D-mannose residues) so far examined from land plants are those from vegetable ivory (Phytelephas macrocarpa).90 96 The... 

Fig. 8 Schematic comparison of cellulose structure formation of BC synthesized in a Hestrin-Schramm (HS) medium (Fig. 3), b glucomannan-modified HS medium. Reprinted with permission from [44]...

Closely associated with cellulose in the wood structure and paper products are other polysaccharides called hemicelluloses, which often have been labeled as the matrix material of wood. In hardwoods the primary hemi-cellulose is a xylan (polymer of xylose), whereas in softwoods the primary hemi-cellulose is a glucomannan, although both of these polysaccharides occur to some extent in both types of wood. The DP of the hemicelluloses is much less than that of cellulose, in the range of 100-200. 

Structures of Several Glucomanno-oligosaccharides Isolated from Enzymic Hydrolyzates of Glucomannans... 

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