ABSTRACT
Konjac glucomannan (KGM) is a high-molecular-weight polysaccharide that was originally extracted from the corms (underground storage organs) of Amorphophallus konjac K. Koch, a perennial plant belonging to the family Araceae. Glucomannan consists of D-mannose and D-glucose units at a molar ratio of 1.6:1.0, connected by (1-4)-glycosidic bonds and is a water-soluble hydrocolloid obtained from konjac flour. Konjac flour is the unpurified raw product from the corms of various species of Amorphophallus as per specifications for konjac flour [INS 425] of the Joint FAO/WHO Expert Committee on Food Additives. Konjac flour is also known under the synonyms konjac mannan, konjac, konnyaku, and konjac glucomannan (JECFA 2006). The European Union authorizes the use of purified forms of glucomannan, namely, konjac gum (E 425 i) and konjac glucomannan (E 425 ii) as food additives; konjac gum is obtained by aqueous extraction, while konjac glucomannan is obtained by washing with water-containing ethanol (EFSA 2017). The chemical characteristics of glucomannan are described in the Merck Index (2006) and in the CAS registry under the number 37220-17-0 (EFSA 2017).
