Sodium Alginate
The short version
The water-soluble sodium salt of seaweed alginate — thickens sauces and cold-sets into gels with calcium.
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Where it comes from
The sodium salt of alginic acid from brown seaweed — the most widely used alginate.
How it's used
Thickener, stabilizer, and gelling agent. Cold-sets into gels on contact with calcium (E509) — the basis of restructured foods (reformed onion rings, pimento strips in olives, fruit pieces) and of culinary 'spherification'. Stabilizes ice cream against ice crystals.
Safety profile
No ADI specified. Not digested; behaves as soluble fiber. Well tolerated; very large amounts can be mildly laxative and bind some minerals.
Physical & chemical properties
White-to-yellow water-soluble powder giving viscous solutions; reacts with calcium to form firm, heat-stable gels.
Regulation worldwide
Permitted in the EU, the US (GRAS), and globally.
Educational information only. Not medical or dietary advice.