Alginic Acid
The short version
A seaweed-derived polysaccharide used to thicken, stabilize, and form heat-stable 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
Extracted from brown seaweeds (kelps such as Laminaria, Macrocystis, and Ascophyllum). A linear polysaccharide of mannuronic and guluronic acids, isolated industrially since the early 20th century.
How it's used
Thickener, gelling agent, and stabilizer, and the parent of the alginate salts (E401–E405). Forms firm, heat-stable gels in the presence of calcium — used in restructured foods, sauces, and bakery fillings.
Safety profile
No ADI specified — regarded as safe. Not digested or absorbed; passes through the gut as soluble fiber. Very high intakes may modestly reduce mineral absorption.
Physical & chemical properties
White-to-brownish fibrous powder. Insoluble in water but swells strongly; soluble and viscous as its sodium salt; gels with calcium ions.
Regulation worldwide
Permitted in the EU, the US (GRAS), and globally without restrictive limits.
Educational information only. Not medical or dietary advice.