Degradation of konjac glucomannan by enzymes in human feces and formation of short-chain fatty acids by intestinal anaerobic bacteria

• Published in: Journal of Nutritional Science and Vitaminology Vol. 44; no. 3; pp. 423 - 436
• Main Author: Matsuura, Y. (Okayama Prefectural Univ., Soja (Japan))
• Format: Journal Article
• Language: English
• Published: Tokyo Center for Academic Publications Japan 01.06.1998
• Subjects: Acetic Acid - metabolism; ACIDE GRAS; ACIDOS GRASOS; Adult; anaerobic intestinal bacteria; ANAEROBIOSE; ANAEROBIOSIS; BACTERIA; Bacteria, Anaerobic - metabolism; BIODEGRADACION; BIODEGRADATION; Biological and medical sciences; Butyric Acid - metabolism; Cellobiose - metabolism; Dietary Fiber; ENZIMAS; ENZYME; ENZYMES; FAECES; FATTY ACIDS; Fatty Acids - biosynthesis; FECES; Feces - enzymology; Female; Fermentation; Food; Formates - metabolism; Fundamental and applied biological sciences. Psychology; Glucose - metabolism; HECES; human feces enzymes; Humans; INTESTIN; Intestine. Mesentery; INTESTINES; Intestines - microbiology; INTESTINOS; konjac glucomannan; Male; MANANOS; MANNANE; MANNANS; Mannans - metabolism; mannobiose; Mannose - metabolism; Middle Aged; Propionates - metabolism; short-chain fatty acids; Vertebrates: digestive system; Human; Short chain; Digestive system; Gut; Lipids; Konjac; Microflora; Fatty acids; Traditional food stuff; Feeding; Plant origin; Enzymatic digestion; Anaerobic fermentation; Carbohydrate; Feces; Glucomannan
• ISSN: 0301-4800; 1881-7742
• DOI: 10.3177/jnsv.44.423

Konjac (konnyaku) glucomannan was examined for its deg radation in human intestines and fermentation products. The konjac glucomannan was degraded almost 100% by soluble enzymes in human feces to give 4-O-β-D-mannopyranosyl-D-mannopyranose (β-1, 4-D-man nobiose), 4-O-β-D-glucopyranosyl-D-glucopyranose (cellobiose), 4-O-β-D glucopyranosyl-D-mannopyranose, and small amounts of glucose and mannose. These three disaccharides were further degraded by a cell associated enzyme(s) to glucose or mannose, or to both. Konjac gluco mannan underwent fermentation by intestinal anaerobic bacteria and produced formic acid, acetic acid, propionic acid, and 1-butyric acid. These fatty acids were different in their proportions among test subjects, their total amounts ranging from 17.1% to 48.8% of the initial konjac glucomannan.