Gel-forming polysaccharides

Using computer modeling, jointly with x-ray fiber diffraction data, the molecular architectures of two different gel-forming polysaccharides have been examined. Preliminary results indicate that the neutral and doubly branched capsular polysaccharide from Rhizobium trifolii can form a 2-fold single helix of pitch 1.96 nm or a half-staggered, 4-fold doublehelix of pitch 3.92 nm. The molecules are likely to be stabilized by main chain — side chain interactions. 

Semisolid systems fulfill a special topical need by being able to cling to the surface of application. Such systems are plastic in behavior, which allows semisolids to be mechanically spread uniformly over a surface as an immobile film. For the production of lipid-free ointments, pastes, and creams, several gel-forming polysaccharides are being used. As an emulsifier they can provide a three-dimensional matrix which... 

The seeds of Tamarindus indica contain polysaccharides which can be extracted with hot water and purified by precipitation with alcohol. The polysaccharide is composed of D-galactose, D-xylose, and D-glucose (Fig. 10). These xyioglucans have been named amyloids since they give a color reaction with iodine similar to starch. The xyioglucans from Tamarindus are gel-forming polysaccharides which are stable in a wide pH range. This type of polysaccharide is mainly used in food industry, but, in some cases, it has been pharmaceutically employed as a substitute for pectin. 

Chandrasekaran, R., Millane, R. P., and Amott, S. (1988a). Molecular structures of gellan and other industrially important gel forming polysaccharides. In Gums and Stabilizers for the Food Industry, Phillips, G. O., Williams, P. A., and Wedlock, D.J. (Eds.), Vol. 4, pp. 183-191. IRL Press, Oxford. 

The most important of these gel forming polysaccharides are (i- and k-) carrageenan, agatfose), and the alginates, all of which are extracted from... 

Clinical studies in healthy subjects demonstrate that the acute addition of the viscous types of dietary fibre such as the gel-forming polysaccharide guar leads to a decrease in postprandial hyperglycaemia by a reduction in gastric-emptying rates and slowing of intestinal carbohydrate absorption. 

Lists of gel-forming polysaccharides, with their molecular structures, are available from several sources,7-10 and other reviews deal with structure alone.11-180 It is only necessary here to summarize the... 

A gel-forming polysaccharide may be isolated from the thickened cell-walls of the cotyledons of the seeds of tamarind (Tamarindus... 

Carrageenan is a generic name for a family of gel-forming polysaccharides, which are commercially obtained by extraction of certain species of red seaweeds... 

Gel-forming polysaccharides like K-carrageenan, alginate, agar or gellan, can be used in plates as a solidifying agent. If polysaccharases are produced, depressions will be visible around the colonies (5). 

Fischer et al, The gel-forming polysaccharide of psyllium husk (Plantago ovata Forsk) , Carbohydrate Research, August 2004 339 2009-2017. 

Harada T, Masada M, Fujimori K, Maeda I. Production of firm, resihent gel- forming polysaccharide by a mutant of Alcaligenes faecalis var. myxogenes 10C3. Agric Biol Chem 1966 30 196-8. 

The conformational behaviour of the extracellular gel-forming polysaccharides from Arthrobacter species has been investigated by n.m.r. relaxation and optical rotation techniques. ... 

Extracellular polysaccharides composed of o-glucose, pyruvic acid, and succinic acid have been isolated from a number of strains of Agrobacterium. The conformational behaviour of the extracellular gel-forming polysaccharides from Arthrobacter species has been investigated by nuclear magnetic resonance relaxation and optical rotation techniques. " A number of the polysaccharides studied showed evidence of an ordered conformation which could be melted out on heating. O-Deacetylation destroyed the ordered conformation of two A. viscosus polysaccharides, whilst O-deacylation of the A. stabilis polysaccharide stabilized the ordered structure. 

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