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Glucomannan

Glucomannan is a polysaccharide complex found in the tuber of Amorphophallus species such as A. konjac, A. kosiana, A. shichitoensis, A. companulatus, A. variabilis and A. oncophyllus. The tuber of Amorphophallus konjac is the source of a well-known foodstuff in China and Japan, namely konjac flour. This flour, which contains a variety of insoluble materials described below as well as a major amount of desirable water-soluble substances, comprises a highly viscous sol of glucomannan and soluble starches when reconstituted in water. Glucomannan is a polysaccharide comprised of D-glucose and D-mannose, which is useful as an ingredient in various foodstuffs, as well as in industrial applications such as films, oil drilling fluids, and paints. A main component of konjac is glucomannan. Glucomannan provides an excellent indigestible dietary fiber of molecules having a molecular weight of several hundred thousand and consisting of glucose and mannose. Konjac has been traditionally used as a food. However, since it requires strong alkalinity in coagulation, an alkali and an alkaline smack remain in konjac, which has restricted the uses of konjac. Konjac coagulum, which is thermally irreversible, is not melted by heating. Konjac coagulum, which is elastic, cannot be made into a paste by grinding.

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