Glucomannan (konjac)
Glucomannan (konjac) suppliers and sourcing guide
Glucomannan is the water-soluble polysaccharide of glucose and mannose stored in the tubers (corms) of konjac, Amorphophallus konjac and related species. The corms are sliced, dried and milled to konjac flour, which can be purified further by washing with ethanol to remove starch, protein and odor, giving a higher-glucomannan powder. It forms very viscous solutions and gels and is used as a thickener, in konjac noodles and in capsule and powder supplements.
- Category
- Fibers
- Also known as
- konjac glucomannan · konjac flour · konjac gum · Amorphophallus konjac · E425
- Facts checked
- November 2026
Forms and grades of glucomannan (konjac)
Suppliers sell different products under the same name. Specify the one you need.
Konjac flour
Milled dried corm, typically around 70 to 80% glucomannan; used as a food thickener and gelling agent.
Purified konjac glucomannan
Ethanol-washed powder, often 85 to 95% glucomannan, with lower odor and higher viscosity.
Viscosity grades
Sold by the viscosity of a 1% solution, from a few thousand to over 30,000 mPa·s.
Particle size grades
Fine mesh grades for capsules and quick hydration, coarser grades for food processing.
What to check on the COA
Compare each result with your own specification when the lot arrives.
- Glucomannan content
- Glucomannan by a colorimetric (3,5-dinitrosalicylic acid) method after hydrolysis, or by the supplier's validated method.
- Viscosity
- Viscosity of a 1% solution with a rotational viscometer after a set hydration time.
- Moisture and ash
- Loss on drying and ash.
- Sulfur dioxide
- Residual sulfite, since corm slices are sometimes treated with sulfites during drying.
- Residual ethanol
- For purified grades washed with ethanol, by gas chromatography.
- Heavy metals
- Lead, arsenic, cadmium and mercury by ICP-MS.
Storage, lots and expiry
Storage and shelf life
Keep konjac powder in sealed, moisture-barrier bags in a cool, dry place; it absorbs water readily and loses viscosity if it gets damp. Suppliers set a best-before or retest date for unopened packaging.
Lots and expiry dates
Viscosity and glucomannan content vary with species, origin and purification, so record both from each COA and test hydration in your product. Note the sulfite result for allergen labeling decisions.
Regulatory status
Facts from regulators and standards bodies, each linked to its source.
FDA added glucomannan in January 2020 to the non-digestible carbohydrates it intends to propose adding to its dietary fiber definition.
Source: fda.gov (opens in a new tab)Health Canada's glucomannan natural health product monograph lists the tuber of Amorphophallus bulbifer, Amorphophallus konjac and Amorphophallus muelleri as source materials.
Source: webprod.hc-sc.gc.ca (opens in a new tab)
This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.
Glucomannan (konjac) suppliers
Manufacturers and distributors whose own websites say they sell it.
We are checking glucomannan (konjac) suppliers now
Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.
Sell glucomannan (konjac)? Request a listingFrequently asked questions
What forms of glucomannan (konjac) can brands buy?
Common forms include konjac flour, purified konjac glucomannan, viscosity grades and particle size grades. Ask each supplier for the specification sheet of the exact grade they quote.
What should the COA for glucomannan (konjac) include?
Expect glucomannan content, viscosity, moisture and ash, sulfur dioxide, residual ethanol and heavy metals, each with its method, specification and result for that lot.
How should glucomannan (konjac) be stored?
Keep konjac powder in sealed, moisture-barrier bags in a cool, dry place; it absorbs water readily and loses viscosity if it gets damp. Suppliers set a best-before or retest date for unopened packaging.
What is the regulatory status of glucomannan (konjac)?
FDA added glucomannan in January 2020 to the non-digestible carbohydrates it intends to propose adding to its dietary fiber definition. Health Canada's glucomannan natural health product monograph lists the tuber of Amorphophallus bulbifer, Amorphophallus konjac and Amorphophallus muelleri as source materials.
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