Guar galactomannan structure

Fig. 24.—Schematic Drawing of Possible Chain Structures for Guar Galactomannan. (X-ray data favor the structure on the right." )...

The general chemistry of the galactomannans has been reviewed by Whistler and Smart" and others,7 " and papers frequently appear that discuss the uses of guar and locust-bean gums in various industrial applications, such as in cosmetics9 and food.10,11 Most of this article deals with investigations of the structural chemistry of galac-... 

Galactomannans have been used as flocculents (for the purification of ores, for example) and a study has been made of the gum structure by electron microscopy. The smallest fiber-diameter for an evaporated film of guar gum was found260 to be 4 nm, but, when a kaolinite-guar gum flocculate was examined, the diameter of the smallest fiber that was attached to the kaolin was found to be 10 nm. It is suggested that flocculation is caused by polymer bridging of the clay particles. 

The disaccharide epimelibiose [0-a-D-galactopyranosyl-(l— 6)-D-mannopyranose] was first isolated by Whistler and Durso202 from a partial hydrolyzate of the D-galactomannan of guar by acid (see also, Ref. 203), and they also elucidated its structure. This disaccharide constitutes the branch points of the main D-galactomannan chain (see Section V,3). 

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