Polysaccharide gels triple helical structure

Curdlan gel formation is heat dependent. This polysaccharide is not soluble in water, but when an aqueous suspension is heated it becomes dear at about 54°C. Furdier heating leads to gel fonnation. The gels are stable over a wide range of pH (3 to 95) and do not melt at temperatures below 100°C. Curdlan gels are formed by cross-linldng, involvii conformational ordering of the exopolysaccharide molecules to give a triple helical structure. 

The melting points and heats of junction formation of curdlan gels depend on the concentration and DP of the polysaccharide [a (1 3)-P-D-glucan from Alcaligenes faecalis. The junction zones of the gels appear to form in regions of aggregation of intertwined helices. X-Ray diffraction studies have revealed that curdlan assumes a triple-helical structure. ... 

X-Ray diffraction studies on the (l->3)-j8-D-gIucan, curdlan, from Alcaligenes faecalls have shown the existence of microfibril formation, and a triple helical structure is proposed for the crystalline form of this polysaccharide. The effects of applied hydrostatic pressure on the gel structures of the polysaccharide have been reported. The elasticity decreases initially with increasing pressure attributed to a decrease of free water as solvent, but then increases as the pressure is increased due to the promotion of hydrogen bonding by compression. 

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