E400: Alginic Acid
Main role: thickening and gelling
Also listed as: algin, alginic acid preparation
What is E400 (Alginic Acid)?
Alginic acid is a polysaccharide associated with brown seaweed. It is the parent acid of the alginate family and helps create structure in suitable food systems. Its behavior differs from its soluble sodium and potassium salts.
What does it do in food?
Its main role is thickening and gelling. Texture ingredients help a recipe control thickness, binding, or separation. Their behavior depends on temperature, acidity, concentration, and other ingredients; two thickeners with similar names may not perform identically.
Food and formulation examples
- Gelling preparations
- Texture-control food systems
- Ingredient stabilization blends
These examples describe formulation roles, not a list of unrestricted legal uses. Availability and permitted applications differ by country and food category.
Label names and ingredient questions
Look for E400, E 400, or the ingredient name. Related names and label terms include algin, alginic acid preparation. A family code can cover more than one specified form; check the full declaration when the distinction matters.
Alginic acid and sodium alginate E401 are related but can hydrate and behave differently. A recipe designed for one should not assume an equal substitution with the other.
Is E400 safe?
The EFSA alginates re-evaluation (2017) is a scientific reference for this group. Its conclusions apply to the uses and exposures considered in that assessment, rather than every possible use or personal circumstance.
A label identifies the ingredient but usually not its concentration. Calculating daily intake requires the amount in the food and the quantities eaten.
Authorization and conditions of use
The Great Britain food additive register lists E400 as Alginic acid. This is an entry subject to its stated conditions, not unrestricted permission for every food. The record links to the applicable authorization terms. For an EU product, use the European Commission food additive database to check the relevant food category and limits. Other countries may use different names or rules.