Fatty acid esters of ascorbic acid

Fatty acid esters of ascorbic acid — primarily ascorbyl palmitate (E304i) and ascorbyl stearate (E304ii) — are oil-soluble antioxidants derived from vitamin C. Unlike ascorbic acid, which dissolves in water, these esters dissolve in fats and oils, making them suitable for protecting lipid-rich products such as vegetable oils, margarines, frying fats, and vitamin supplements from oxidative rancidity and off-flavour development.

JECFA's ADI is "not specified," evaluated in 1973. When consumed, ascorbyl esters are hydrolysed in the gut to ascorbic acid and the corresponding fatty acid — both naturally occurring compounds. There is no distinct toxicological concern for either metabolite at any realistic dietary intake, and the safety profile is essentially equivalent to that of vitamin C itself.

Permitted broadly in the EU, US (GRAS), UK, and most global jurisdictions, fatty acid esters of ascorbic acid are considered among the safest antioxidant additives available. They are common in vegetable oils, salad dressings, and chewing gum base. Commercial versions are almost universally plant-derived, making them suitable for vegan and vegetarian consumers. Their role as a vitamin C derivative also means they contribute no novel chemical entities to the diet beyond compounds the body already handles routinely.