Ammonium alginate
A safe, natural thickener derived from seaweed.
- Category
- Thickeners
- Vegan
- Yes
- Vegetarian
- Yes
What it is
A natural carbohydrate extracted from brown seaweed used as a thickener and gelling agent.
How it is used in food
Ammonium alginate is extracted from brown seaweed and thickens, stabilises and gels water-based foods at low concentrations. Alginates hold water and fat in emulsions, prevent ice-crystal growth in frozen desserts, and let manufacturers build texture without added fat. As an unabsorbed soluble fibre it also increases viscosity in the gut, which can modestly slow gastric emptying and increase satiety.
Commonly found in- Ice cream
- Sauces
- Desserts
Health and safety
Generally safe; it is an indigestible fiber that passes harmlessly through the gut.
EFSA re-evaluated alginic acid and its salts in 2017 and concluded there was no safety concern at reported use levels, keeping the group ADI 'not specified'; the panel noted alginates are not absorbed intact and are largely fermented or excreted. Studies in animals and humans show no genotoxicity or carcinogenicity. The practical caveats are that high intakes of any viscous soluble fibre can cause bloating or loose stools, and that alginates can bind some minerals in the gut lumen, though this has not been shown to affect mineral status at food-use levels.
Regulatory status
| Region | Status | Notes |
|---|---|---|
| Australia & New Zealand FSANZ |
Permitted | Permitted under the FSANZ Food Standards Code. |
| European Union EFSA / European Commission |
Permitted | Authorised for food use under EU regulations (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
- E403
Worth knowing
Alginate is the chemistry behind 'spherification' — the technique that made popping caviar-like spheres a signature of modernist cooking — because it gels instantly on contact with calcium ions rather than needing heat. The same instant calcium gelling is used medically in alginate wound dressings and in raft-forming antacids that float on stomach contents.
Conclusion
A safe, natural thickener derived from seaweed.
References
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Open the appEntry last reviewed 2026-07-28.
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