CRYSTAL-STRUCTURES OF MANNAN AND GLUCOMANNANS

Mannan and glucomannans are related polysaccharides that are widely di stributed as reserve materials of certain plants, as well as in the ce ll walls of some softwoods and a variety of vegetative tissues. They a re often crystalline in vivo and occur as a number of crystalline allo morphs. The glucomannan from the konjac plant is also exploited commer cially as a thickening and gelling agent. Xray diffraction can be used to visualize hydrated polymer systems at atomic resolution, and the m olecular and crystal structures so derived can be used to study struct ure-function relationships. The different crystalline allomorphs of ma nnan are described and compared with those of cellulose. The crystal s tructures of konjac mannan are described and implications for the mole cular basis of its gel-forming behaviour discussed.