What is E304?
Complete guide to understanding E304 (Ascorbyl Palmitate and Stearate) in your food
The Quick Answer
E304 is a fat-soluble form of vitamin C created by chemically binding ascorbic acid (vitamin C) to palmitic or stearic acid (fatty acids)—functioning as an antioxidant and preservative that prevents fats and oils from becoming rancid.
It’s used in oils, snacks, baked goods, dairy products, and other fatty foods where water-soluble vitamin C (E300) would be less effective.
It is considered safe by regulatory authorities. EFSA concluded there is no safety concern at approved use levels, though no numerical ADI was established due to limited toxicological data. E304 is assumed to completely break down into vitamin C and fatty acids during digestion.
📌 Quick Facts
- Category: Synthetic fat-soluble antioxidant (vitamin C ester)
- Types: E304(i) = Ascorbyl palmitate (C₂₂H₃₈O₇); E304(ii) = Ascorbyl stearate (C₂₄H₄₀O₇)
- Source: Chemically created by esterifying ascorbic acid with palmitic or stearic acid
- Function: Fat-soluble antioxidant; prevents rancidity in oils/fats; more effective than water-soluble E300 in fatty products
- Found in: Vegetable oils, snacks, baked goods, dairy products, nuts, prepared meals, cosmetics, skincare products
- Safety Status: FDA GRAS; EFSA approved; approved in EU, USA, Canada, Australia, New Zealand
- ADI: Not established numerically; EFSA concluded no safety concern at food-use levels
- Key Feature: Fat-soluble unlike water-soluble E300; more stable in fatty products; assumed complete hydrolysis to vitamin C and fatty acids
What Exactly Is It?
E304 is a fat-soluble vitamin C ester produced by chemically binding ascorbic acid (vitamin C) with palmitic acid (16-carbon fatty acid) or stearic acid (18-carbon fatty acid).
Two forms exist:
• E304(i) – Ascorbyl Palmitate: Chemical formula C₂₂H₃₈O₇; ester of ascorbic acid and palmitic acid; molecular weight 414.55
• E304(ii) – Ascorbyl Stearate: Chemical formula C₂₄H₄₀O₇; ester of ascorbic acid and stearic acid; molecular weight 442.58
Production: Food-grade E304 is manufactured by esterifying ascorbic acid with the fatty acid using chemical synthesis (acylation). The result is a fat-soluble powder that looks like white to yellowish-white crystalline material.
Mechanism: E304 functions identically to E300 (ascorbic acid) as an antioxidant—donating electrons to neutralize free radicals before they can damage fats and cause rancidity. However, because E304 is fat-soluble, it disperses throughout fatty/oily products more effectively than water-soluble E300.
Key functional assumption: EFSA and regulatory authorities assume that E304 completely hydrolyzes (breaks down) in the gastrointestinal tract into ascorbic acid (vitamin C) and the fatty acid (palmitate or stearate) during digestion. This assumption is based on in vitro studies, though human absorption studies are limited.
Where You’ll Find It
E304 appears in fatty and oily food products:
• Vegetable oils (particularly oils high in unsaturated fatty acids prone to oxidation)
• Snack foods (potato chips, crackers)
• Baked goods (cakes, cookies, pastries with added oils/fats)
• Butter and margarine
• Nuts and nut products
• Prepared meals and convenience foods
• Dairy products (milk fat, cheese)
• Meat products with high fat content
• Food colorings (E160, E161) as protection against oxidation
• Cosmetics and skincare products (as both antioxidant and vitamin C source)
• Topical pharmaceutical preparations
E304 is less common than water-soluble E300 because it is only used where fat-solubility provides functional advantage (fatty/oily products). In aqueous foods (beverages, canned fruits), E300, E301, or E302 are preferred.
Why Do Food Companies Use It?
E304 serves critical functions in fatty foods:
Superior effectiveness in oils and fats: Because E304 is fat-soluble, it disperses throughout fatty/oily products effectively, whereas water-soluble E300 would separate from the fat phase. This makes E304 dramatically more effective at preventing rancidity in oils and fatty products.
Prevents oxidation of unsaturated fats: Particularly valuable in plant oils high in unsaturated fatty acids (prone to rapid oxidation). E304 preserves oil freshness for months longer than without protection.
Stabilizes fat-soluble colors: E304 prevents oxidation of fat-soluble food colorings (E160, E161), maintaining color stability in products.
Heat stability: E304 resists degradation better than water-soluble E300 in high-temperature food processing.
Dual benefit—preservation and vitamin fortification: E304 serves as both preservative and vitamin C source (after hydrolysis to ascorbic acid).
Regulatory approval: Globally approved with positive safety assessments, reducing manufacturer liability concerns.
Is It Safe?
Yes—E304 is considered safe by regulatory authorities. EFSA concluded there is no safety concern at approved food-use levels, though no numerical ADI was established due to limited toxicological data. Safety is based on the assumption that E304 completely hydrolyzes to vitamin C and fatty acids, which are both safe.
The FDA classifies ascorbyl palmitate and stearate as GRAS (Generally Recognized as Safe).
The EFSA’s 2015 re-evaluation of E304(i) and E304(ii) concluded: “…there is no safety concern for the use of ascorbyl palmitate (E 304(i)) and ascorbyl stearate (E 304(ii)) as food additives at the reported uses and use levels.”
The EFSA also assessed E304 in infant formula (2020) and concluded: “…the intake of both ascorbic acid and palmitate, at the maximum permitted levels for food according to FC 13.1.1 and food according to FC 13.1.5.1 does not raise health concerns for infants below 16 weeks of age.”
✓ GREEN SAFETY RATING – NO CONCERNS: E304 has:
• No documented genotoxicity (DNA damage); Ames test negative
• No documented carcinogenicity; some in vitro studies suggest possible anti-cancer properties
• No documented reproductive or developmental toxicity
• No organ toxicity at food-use levels
• Very low acute toxicity
• Assumed complete hydrolysis to safe components (vitamin C + palmitic/stearic acid)
• Palmitic acid component: “not specified” ADI, long history of safe use in food fats
• Ascorbic acid component: no safety concerns at food levels
• Safe in infant formula at maximum permitted levels
Safety is based on: (1) low acute toxicity, (2) assumed complete harmless hydrolysis to vitamin C and fatty acids, (3) extensive history of safe use of component fatty acids in food, and (4) safety of ascorbic acid at food levels.
What Are The Health Concerns?
E304 has no documented health concerns at food-use levels. However, some considerations exist:
Limited toxicological data: EFSA noted that “biological data on ascorbyl palmitate and stearate are sparse,” which is why no numerical ADI was established. However, this reflects data gaps rather than identified safety problems. The available data support safety.
Complete hydrolysis assumption (not fully proven in humans): EFSA assumes E304 completely breaks down into vitamin C and fatty acids during digestion. While in vitro studies support this, comprehensive human absorption studies are limited. However, this assumption is conservative and protective.
Fatty acid content (minimal concern): E304 contributes palmitic or stearic acid to diet (~57.5% of E304 mass). However, these are common dietary fatty acids consumed in far larger amounts from fats, oils, nuts, and meats. The additive represents only ~3% of typical daily palmitic acid intake.
Oxidative stability in sunlight (theoretical concern): One source suggests E304 may undergo lipid peroxidation (oxidative degradation) when exposed to sun, though studies were limited to cell culture. This is relevant only for topical products, not food.
Stability claims (sometimes overstated): Marketing sometimes claims E304 is more stable than ascorbic acid; research suggests this may be overstated. However, for food preservation purposes, E304’s fat-solubility (not necessarily superior stability) is the key advantage.
No documented adverse effects in humans: EFSA noted “post-marketing information shows that adverse effects were rarely reported.”
Safe in infant formula: EFSA explicitly confirmed safety in infant formula at maximum permitted levels.
Natural vs Synthetic Version
E304 is entirely synthetic—it does not occur naturally in foods.
It is created through chemical esterification of ascorbic acid (vitamin C) with palmitic or stearic acid (fatty acids). While both starting materials are natural, the ester is a synthetic combination.
However, E304 is designed to be completely hydrolyzed back into natural components (vitamin C and fatty acids) during digestion, making it functionally equivalent to consuming vitamin C and dietary fat separately.
Natural Alternatives
Want to avoid E304?
Natural antioxidant alternatives include:
• Vitamin E/Tocopherols (E306) – natural fat-soluble antioxidant (also found in oils, nuts)
• Rosemary extract – natural fat-soluble antioxidant
• Green tea extract – natural antioxidant (though water-based)
• Ascorbic acid (E300) – water-soluble vitamin C (less effective in fats)
• Accept shorter shelf-life – use oils/fats without preservation; consume quickly
The Bottom Line
E304 (Ascorbyl Palmitate/Stearate) is a fat-soluble form of vitamin C that functions as an antioxidant and preservative in fatty foods. EFSA and FDA consider it safe at approved food-use levels, though no numerical ADI was established due to limited toxicological data. Safety is based on assumed complete hydrolysis to vitamin C and fatty acids.
Regulatory Safety Conclusion: EFSA explicitly concluded “there is no safety concern” at reported uses and levels. FDA GRAS approval reflects same conclusion.
Key Safety Assumption: E304 is assumed to completely break down into vitamin C and fatty acids during digestion, both of which are safe. This assumption is supported by in vitro studies and has not been contradicted by post-marketing safety data.
Infant Safety Confirmed: EFSA explicitly confirmed safety in infant formula at maximum permitted levels—one of the strictest regulatory standards.
Fat-Solubility Advantage: The primary functional advantage of E304 over water-soluble E300 is fat-solubility, enabling effective antioxidant protection in oils, fats, and fatty foods where water-soluble forms cannot disperse effectively.
Limited Toxicological Data (Not a Safety Problem): EFSA noted biological data are sparse, which is why no numerical ADI was established. However, this reflects data gaps rather than identified safety problems. Available data support safety.
No Adverse Effects Documented: Post-marketing surveillance shows “adverse effects were rarely reported,” supporting real-world safety in humans.
Fatty Acid Component Safety: Palmitic and stearic acids have long history of safe dietary use (present in fats, oils, meats, dairy). E304 adds only ~3% of typical daily dietary intake of these fatty acids.
Recommendation: E304 is safe for food use at approved levels. It is particularly valuable as a fat-soluble antioxidant in oils and fatty foods. Like other E300-E303 compounds, E304 is a form of vitamin C and is beneficial rather than concerning. For individuals preferring to avoid all synthetic additives, natural alternatives (vitamin E extract, rosemary extract) exist but are less effective in fatty products.