E401 - sodium alginate

At a glance

• What it is: the sodium salt of alginic acid from brown seaweeds (kelp).
• What it does: thickener, stabiliser, emulsifier, humectant (holds moisture), and sequestrant (binds metals).
• Common in: ice cream, sauces, dressings, fruit fillings, bakery creams, restructured foods, and some plant‑based meats and dairy.
• Heat and acid: works across a wide pH range and is heat‑tolerant in many recipes.
• Dietary notes: vegan, gluten‑free, and not made from animal products.
• Production: extracted from seaweed with an alkaline wash, purified, and converted to the sodium form.
• Regulation: permitted in the U.S. and EU when used according to good manufacturing practice.

Why is sodium alginate added to food?

Food makers use sodium alginate to improve texture and stability. It thickens liquids, helps emulsions (oil‑in‑water mixes) stay mixed, and prevents ice crystals and weeping in frozen and chilled foods. It is the sodium salt of alginic acid and is part of the alginate family along with potassium alginate, ammonium alginate (E403), and calcium alginate (E404).
In the United States, the Food and Drug Administration (FDA) lists sodium alginate as Generally Recognized as Safe (GRAS) for use as a stabilizer, thickener, and emulsifier under good manufacturing practice (GMP). GMP means using only the amount needed to get the intended effect.¹ The European Union (EU) sets identity and purity specifications for E401 to ensure consistent quality.²

What foods contain sodium alginate?

Sodium alginate shows up in many everyday foods. Examples include:

• Dairy and non‑dairy frozen desserts and soft‑serve
• Sauces, gravies, and salad dressings
• Fruit fillings, jams, pie and pastry creams
• Processed meats and plant‑based restructured foods
• Ready‑to‑eat desserts and gelled products

In the EU, E401 is authorised in many food categories under Regulation (EC) No 1333/2008, often at levels “quantum satis,” which means only as much as needed for the effect.³ In the U.S., it is GRAS for general food use, following GMP.¹ You may also see foods that use similar hydrocolloids, such as carrageenan, xanthan gum, gellan gum, pectins, guar gum, or locust bean gum.

What can replace sodium alginate?

The best substitute depends on the recipe and processing:

• For general thickening: xanthan gum or guar gum
• For creamy dairy textures: locust bean gum or carrageenan
• For glossy fruit fillings: pectins or gellan gum
  Keep in mind that each hydrocolloid behaves differently with heat, acid, sugar, and salt, so small test batches help dial in texture.

How is sodium alginate made?

Manufacturers extract alginates from brown seaweeds such as kelp using an alkaline solution, filter and purify the extract, and then convert it to the sodium salt. The material is dried and milled to a powder that meets purity and identity specifications.² In foods, sodium alginate can interact with calcium to set structure; cooks sometimes pair it with calcium salts such as calcium chloride for firm gels.

Is sodium alginate safe to eat?

Yes. In the U.S., sodium alginate is GRAS when used in line with good manufacturing practice, meaning only as much as needed for its function.¹ Internationally, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) assigned alginic acid and its salts an Acceptable Daily Intake (ADI) of “not specified,” indicating low toxicity at typical use levels.⁴ As with many fibers and gums, very high intakes may cause digestive discomfort in some people.

Does sodium alginate have any benefits?

From a food technology view, it provides stable thickness, helps hold water in gels and fillings, and can improve freeze‑thaw stability. It also supports clean slicing and bite in restructured and plant‑based foods. It is not a nutrient and is not used for a health effect in foods.

Who should avoid sodium alginate?

• People on strict sodium‑restricted diets may prefer to limit added sources of sodium, even though alginate is used in small amounts.
• Anyone with known sensitivity to seaweed‑derived ingredients should avoid it.
• For infants and toddlers, follow product‑specific guidance; young children can be more sensitive to thickeners in general.

Myths & facts

• Myth: Sodium alginate is a synthetic chemical.
  Fact: It is extracted from brown seaweed and refined for food use.⁴
• Myth: It adds a lot of sodium to your diet.
  Fact: In both the EU and U.S., it is used at the minimum level needed (EU “quantum satis”; U.S. GMP), so the sodium contribution is usually small.³
• Myth: It’s the same as carrageenan.
  Fact: Both are seaweed gums, but they have different chemistry and textures, so they are not interchangeable in every recipe.

sodium alginate in branded foods

On labels, look for “sodium alginate,” “E401,” or simply “alginate.” It’s common in ice cream, soft‑serve mixes, sauces and dressings, fruit fillings, bakery creams, and many plant‑based alternatives. You’ll also see it in some restructured foods where a firm, clean slice is needed.

References

Footnotes

1. Sodium alginate — 21 CFR 184.1724. https://www.ecfr.gov/current/title-21/section-184.1724 ↩ ↩² ↩³

2. Specifications for food additives — Commission Regulation (EU) No 231/2012. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩ ↩²

3. Food additives regulation — Regulation (EC) No 1333/2008. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008R1333 ↩ ↩²

4. Alginic acid and its salts (evaluation; ADI “not specified”) — JECFA/WHO. http://www.inchem.org/documents/jecfa/jecmono/v26je01.htm ↩ ↩²