Konjac E425
natural — Primarily plant-derived.
Amorphophallus konjac glucomannan
CAS: 37220-17-0
Factual Regulatory Reference
This database provides factual regulatory information compiled from official government sources. It does not constitute medical, nutritional, or safety advice. Regulatory status varies by country and is subject to change. Always refer to your local regulatory authority for the most current information.
What Is Konjac?
Konjac (konjac glucomannan) is a high-viscosity water-soluble dietary fiber extracted from the tubers of Amorphophallus konjac plants, grown primarily in Japan and China. It forms extremely viscous solutions and heat-stable gels (with alkali treatment) and has among the highest water-holding capacity of any food hydrocolloid. Used in Asian cuisine (konnyaku noodles and tofu), and globally as a thickener, stabilizer, and gelling agent. EFSA reviewed konjac glucomannan in 2017. It is not approved in EU infant formulas due to aspiration hazard at high gel concentrations. Approved in EU, USA, Japan, Canada, and Australia.
? Did You Know?
Konjac occurs naturally in konjac plant corm (Amorphophallus konjac). Many people consume it daily without realizing it's also a listed food additive.
Beyond food, Konjac is also used in cosmetics, medicine, household products. Its versatility makes it one of the most multi-purpose chemical compounds in everyday life.
In the EU, Konjac has a "quantum satis" authorization — Latin for "as much as needed." This means there's no specific maximum limit; manufacturers use only what's technologically necessary.
Regulatory Analysis
Konjac (E425) is exceptional among food additives in that its principal regulatory controversy concerns a physical hazard rather than chemical toxicology. Mini-cup konjac jellies caused multiple choking deaths, primarily in children and elderly persons, because their elastic, non-disintegrating gel texture can conform to the throat and resist expulsion. The EU banned konjac in mini-cup jelly confections under Commission Decision 2004/374/EC; the FDA issued import alerts following similar incidents in the USA in 2002. Australia and New Zealand have also banned the mini-cup format. Regulatory action was thus format-specific and aimed at product design, not at the additive itself. Konjac powder as a thickener, konjac noodles (shirataki), and dietary fiber supplements all remain approved across major jurisdictions. EFSA has not established an ADI because konjac glucomannan presents no identified toxicological concern at food-use concentrations; the regulatory attention is instead focused on product design standards for gel confections.
Detailed Regulatory Assessment
European Union (EFSA)
Approved with restrictions. Mini-cup jelly containing konjac is banned due to choking hazard.
United States (FDA)
FDA issued warnings about konjac candy/gel confections due to choking hazard. Import alerts in place for mini-cup jelly products.
Japan (MHLW)
Traditional food with centuries of use. Warnings issued about choking hazards, especially for children and elderly.
Acceptable Daily Intake (ADI)
International Standard (JECFA)
mg/kg body weight per day
European Standard (EFSA)
Natural Occurrence
A water-soluble dietary fiber extracted from the corm (bulb) of the konjac plant, native to Southeast Asia. Traditional Japanese food for over 1,000 years, known as konnyaku.
Manufacturing
Konjac corms are harvested, washed, dried, and ground into flour. Glucomannan is extracted and purified from the flour. The gel form requires treatment with alkali (calcium hydroxide) to form a stable gel structure.
Applications Beyond Food
Used in facial cleansing sponges (konjac sponges) and as a thickener in skincare products.
Sold as a dietary fiber supplement for weight loss, cholesterol reduction, and blood sugar management.
Traditional Japanese New Year food (osechi ryori)