E304II - Ascorbyl stearate

At a glance

This section gives a quick overview before diving deeper.

• What it is: a fatty acid ester of vitamin C used as an antioxidant
• What it does: slows oxidation in oils and fat-rich foods
• Where it appears: snacks, bakery fillings, margarines, and edible oils
• Regulatory status: authorized in the EU as E304ii within the E304 group
• Typical amount: used at low levels, just enough to protect the food

Why is Ascorbyl stearate added to food?

Manufacturers add ascorbyl stearate to delay oxidation in fats and oils, which helps prevent off-flavors and the “stale” taste of rancidity. It belongs to the E304 group of fatty acid esters of ascorbic acid, approved as antioxidants in the EU.¹ EFSA (the European Food Safety Authority) has reviewed E304 and confirmed its antioxidant role in foods.²

What foods contain Ascorbyl stearate?

You’ll most often find it in foods that are rich in fat or oil, where it helps protect quality. Examples include edible oils and fats, margarines and spreads, nut and seed products, pastry creams and fillings, and some fried or baked snacks. These uses align with its authorization as an antioxidant under EU additive rules.³ EFSA’s re‑evaluation notes its use to stabilize fats and oils against oxidation in a variety of foods.²

What can replace Ascorbyl stearate?

Depending on the recipe and regulations, formulators may choose other antioxidants or synergists:

• Other ascorbates: ascorbic acid or ascorbyl palmitate
• Tocopherols: tocopherol-rich extract or alpha-tocopherol
• Phenolic antioxidants: butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), or extracts of rosemary
• Synergists and acidulants that help antioxidant systems: citric acid

How is Ascorbyl stearate made?

Ascorbyl stearate is produced by esterifying L‑ascorbic acid (vitamin C) with stearic acid, yielding primarily the monoester. Food law in the EU sets identity and purity specifications for E304, including stearate and palmitate forms.¹

Is Ascorbyl stearate safe to eat?

Based on its review of data (including how the body handles it), EFSA concluded that ascorbyl stearate as used in foods does not pose a safety concern at the reported use levels.² This conclusion applies to the E304 group (ascorbyl palmitate and ascorbyl stearate) evaluated as food additives.²

Does Ascorbyl stearate have any benefits?

Its main benefit is technological: it slows oxidation, which helps keep oils, nuts, and fat-containing foods tasting and smelling fresh. While it is derived from vitamin C, it is added for preservation, not as a meaningful source of vitamin C in the diet.

Who should avoid Ascorbyl stearate?

Most people do not need to avoid E304ii. Anyone who has been advised to limit ascorbate additives, or who prefers to avoid additives altogether, can check labels for “ascorbyl stearate” or “E304ii.” If you have specific medical or dietary concerns, consult a healthcare professional.

Myths & facts

• Myth: “It’s a preservative that kills bacteria.” Fact: Ascorbyl stearate is an antioxidant; it slows oxidation but does not act as an antimicrobial.
• Myth: “It’s the same as taking vitamin C.” Fact: It’s used at small amounts to protect foods and is not intended as a vitamin supplement.
• Fact: In the body, ascorbyl esters are broken down to ascorbic acid and fatty acids before absorption.⁴

Ascorbyl stearate in branded foods

On ingredient lists, look for “ascorbyl stearate” or “E304ii.” It appears most often in oil-based products like cooking oils, margarine and spreads, nut butters, confectionery fillings, and some baked or fried snacks. It is usually present at very low levels, just enough to help guard against rancidity.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 laying down specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008 — European Commission. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩ ↩²

2. Re-evaluation of ascorbyl palmitate (E 304(i)) and ascorbyl stearate (E 304(ii)) as food additives — EFSA Journal (2015). https://efsa.europa.eu/en/efsajournal/pub/4085 ↩ ↩² ↩³ ↩⁴

3. Regulation (EC) No 1333/2008 on food additives — European Parliament and Council. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008R1333 ↩

4. Toxicological evaluation of some food additives including anticaking agents and ascorbyl esters — WHO JECFA Monographs (IPCS/INCHEM). http://www.inchem.org/documents/jecfa/jecmono/v35je03.htm ↩