Variations of konjac glucomannan (KGM) from Amorphophallus konjac and its refined powder in China

Konjac glucomannan (KGM) is a water-soluble dietary fiber extracted from tubers of Amorphophallus konjac native to China. It has a low caloric content and is a soluble dietary fiber, used in foods and medicine ingredients. This paper reports changes of KGM from Amorphophallus konjac native in the southern part of China to KGM obtained in transplanting trials in the northern part of China. Fresh raw rhizoid-tuber of Amorphophallus konjac contains KGM of 8.03-12.43%. Its refined powder contains KGM ranging from 71.6 to 51.3%, whereas superclass purified powder extracted from tubers of Amorphophallus konjac contains more than 90% KGM, with a maximum value up to 96.9%. The KGM contents in tubers of transplanted Amorphophallus konjac in the northern temperate zone in middle Shaanxi Province in this study range from 27.65 to 47.59%, all of which are less than a mean value of these (54.39%) in the original tuber. It may be proposed that transplanting Amorphophallus konjac from its native land in the subtropical and tropical zone to the northern temperate zone in the northern part of China would be feasible. (C) 2003 Elsevier Ltd. All rights reserved.