ScanWise
E424 · Thickeners

Curdlan

No known risk

A highly functional and safe microbial fiber.

Category
Thickeners
Vegan
Yes
Vegetarian
Yes

What it is

A bacterial exopolysaccharide that forms a highly elastic gel when heated.

How it is used in food

Curdlan is a β-1,3-glucan produced by fermentation with Agrobacterium species, and its distinctive property is heat-set gelling: heated above about 80 °C it forms a firm, thermo-irreversible gel that survives retorting, freezing and reheating. That makes it valuable in noodles, processed meat and surimi, tofu-style products and dumpling fillings, where it holds shape and water where other hydrocolloids melt. It is also fully indigestible, contributing fibre without calories.

Commonly found in
  • Vegan meats
  • Noodles
  • Jellies

Health and safety

Generally recognized as safe (GRAS). It passes through the digestive tract largely intact as dietary fiber.

Curdlan is GRAS in the United States and approved as a food additive in Japan, Korea, Taiwan and elsewhere; JECFA evaluated it and allocated an ADI 'not specified' after subchronic and reproductive-toxicity studies showed no adverse effects. It is not on the EU list of permitted additives, so it is not found in European products. Because it is a β-1,3-glucan it has been studied for immune-modulating activity, and its water-insoluble nature means it is largely excreted rather than fermented, so gastrointestinal effects are milder than with soluble fibres.

Regulatory status

RegionStatusNotes
Australia & New Zealand
FSANZ
Permitted Permitted under the FSANZ Food Standards Code.
European Union
EFSA / European Commission
Not approved Not on the EU authorised list of food additives (Annex II).
United States
FDA (Food and Drug Administration)
Permitted Authorised for food use by the FDA (often GRAS for standard additives).

Identification on labels

E-number
E424

Worth knowing

Curdlan is unusual among hydrocolloids in forming two different gels from the same solution: heating to around 60 °C gives a soft, springy, reversible 'low-set' gel, while heating past 80 °C produces a firm irreversible 'high-set' gel. Japanese manufacturers exploited this to build texture into foods that must be sterilised in the package.

Conclusion

A highly functional and safe microbial fiber.

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Entry last reviewed 2026-07-28.

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