E401: Sodium Alginate
Main role: thickening and calcium-triggered gelling
Also listed as: sodium algin
What is E401 (Sodium Alginate)?
Sodium alginate is a seaweed-derived polysaccharide salt that thickens water-based foods. In the presence of suitable calcium ions it can form a gel, a property used in structured foods and culinary spherification.
What does it do in food?
Its main role is thickening and calcium-triggered 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
- Sauces
- Structured fruit-style preparations
- Spherification recipes
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 E401, E 401, or the ingredient name. Related names and label terms include sodium algin. A family code can cover more than one specified form; check the full declaration when the distinction matters.
Calcium availability changes alginate's behavior. In a recipe, adding calcium chloride E509 or calcium lactate E327 is a separate step from adding the alginate itself.
Is E401 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 E401 as Sodium alginate. 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.