GLUCOMANNAN
CAS Number:11078-31-2
Molecule Formula:C24H42O21
Molecular Weight:666.6
Glucomannan is a water-soluble polysaccharide that is considered a dietary fiber.
Glucomannan is a hemicellulose component in the cell walls of some plant species.
Glucomannan is a food additive used as an emulsifier and thickener.
Products containing glucomannan, under a variety of brand names, are marketed as dietary supplements with claims they can relieve constipation and help lower cholesterol levels.
Since 2010 they are legally marketed in Europe as helping with weight loss for people who are overweight and eating a diet with restricted calories, but as of 2020 there was no good evidence that glucomannan helped weight loss.
Supplements containing glucomannans pose a risk for choking and bowel obstruction if they are not taken with sufficient water.
Other adverse effects include diarrhea, belching, and bloating; in one study people taking glucomannans had higher triglyceride levels.
Glucomannans are also used to supplement animal feed for farmed animals, to help the animals gain weight more quickly.
-Description-
Glucomannan is a linear polysaccharide comprising 1,4-β-linked D-glucosyl and D-mannosyl residues, where the glucose:mannose (Glc:Man) ratio varies considerably.
Konjac (Amorphophallus konjac) glucomannan has a Glc:Man ratio of approx. 2:3, Aloe vera glucomannan a ratio of 1:2, and salep (Orchis mureo) glucomannan has a ratio of approximately 1:4. All of the polysaccharides are acetylated, which imparts water solubility.
Glucomannans are major cell-wall reserve carbohydrates in tubers of several plant genera.
At certain stages in the development of the plants, the glucomannan is degraded and serves as an energy source. The only industrially exploited glucomannan is konjac.
Like carob galactomannan, this polysaccharide interacts with agar, carrageenan and xanthan to form solutions of increased viscosity or gels.
This interaction is exploited in the pet-food industry in canned dog food.
Recently, glucomannan has also been used in jelly sweets.
In this application, the glucomannan has been found to be dangerous, leading to choking deaths of some consumers.
This has led to a ban of these types of sweets in Europe and America, and a need for an accurate analytical procedure for glucomannan analysis.
-Chemical Properties-
Raw glucomannan is a soluble, fermentable, and highly viscous dietary fiber from the elephant yam or konjac plant, native to Asia.
Konjac glucomannan (KGM) is water soluble and a viscous dietary fiber due to its high water absorbing capacity.
The chemical structure of glucomannan consists in an 8:5 mannose:glucose ratio, linked by b-glycosidic bonds, making raw glucomannan the highest molecular weight and viscosity of any other known dietary fibers.
Molecular Weight:666.6
XLogP3-AA:-9
Hydrogen Bond Donor Count:14
Hydrogen Bond Acceptor Count:21
Rotatable Bond Count:10
Exact Mass:666.22185834
Monoisotopic Mass:666.22185834
Topological Polar Surface Area:348 Ų
Heavy Atom Count:45
Formal Charge:0
Complexity:918
Isotope Atom Count:0
Atom Stereocenter Count:19
Atom Stereocenter Count:1
Bond Stereocenter Count:0
Bond Stereocenter Count:0
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes
-Biological Functions-
Weight Management: Glucomannan is a soluble fiber with a high molecular weight and viscosity compared to other fibers, providing enhanced support for weight management.
Significant mean weight loss was observed in one 8-week double blind trial, an effect that may be due to the effect of konjac glucomannan on satiety.
A later study demonstrated that addition of a resistance and endurance exercise training program to a glucomannan-rich diet provides enhanced support for healthy body composition, lipid metabolism and triglycerides.
Cardiovascular Health: In several controlled trials, konjac glucomannan supported healthy lipid metabolism and triglyceride levels, possibly by promoting healthy bile acid secretion.
Additionally, it supports healthy glucose utilization and vascular function to support overall cardiovascular health.
GI Health: As a dietary fiber, konjac glucomannan supports GI regularity.
Research indicates that it also promotes healthy microflora balance, enhancing the growth of lactobacillus and bifidobacteria for a healthy gastrointestinal tract.
-Mode of action-
Glucomannan improved blood lipid levels by enhancing fecal excretion of neutral sterol; and bile acids bind biliary salts, taking the blood lipids with them.
Lipid-lowering action may include an inhibition of cholesterol absorption in the jejunum (19) and bile acid absorption in the ileum (33) mediated by viscosity or less postprandial stimulation of 3-hydroxy3-methylglutaryl-CoA reductase.
Raw glucomannan is thought to prolong gastric emptying time, which increases satiety, reduces body weight, decreases the ingestion of foods that increase cholesterol and glucose concentrations, reduces the postprandial rise in plasma glucose, suppresses hepatic cholesterol synthesis, and increases the fecal elimination of cholesterol-containing bile acids.
There is no evidence that nonviscous versions more commonly marketed in the U.S. provide any health effects.
-Uses-
Human food additive:
Glucomannan is a food additive used as an emulsifier and thickener with the E number E425(ii).
Glucomannan-rich salep powder is responsible for the unique textural properties of salep dondurma, a mastic-flavored stretchable and chewy ice cream of Turkish origin.
Human dietary supplement:
Glucomannan is an ingredient in a variety of dietary supplement products marketed with claims that they aid in weight loss, but medical research has found no good evidence to support its use for this purpose.
The claim is that it makes a gel when mixed with water, which can take up space in the stomach and linger there longer than water alone would, inducing a person to feel full after having eaten a smaller amount of food.
In Europe and Canada, glucomannan dietary supplements can be marketed with claims to lower cholesterol levels and to relieve constipation.
Data from a randomized controlled clinical trial suggests that glucomannan dietary supplements help regulate the hormone ghrelin and might help control appetite in people with Type II Diabetes.
Dietary supplements for animals:
It is also used as dietary supplement for farmed animals in order to help them gain more weight from food, called the feed conversion ratio. The effect of mannan oligosaccharides on animal performance was analysed in meta-analyses for poultry, pigs, and calves.
-Synonyms-
Glucomannoglycan
76081-94-2
(Glucomannan)n
(Glucomannan)n+1
CHEBI:17020
C01810