Calcium ascorbate

E number E302INS 302CAS 5743-27-1

Used as an antioxidant.

Calcium ascorbate is a vitamin C salt used as an antioxidant, notably to stop cut apples and potatoes browning.

Where it is and isn’t permitted

Status of Calcium ascorbate by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
Jurisdiction	Status	Scope and limits	Citation
United StatesFood and Drug Administration	Permitted		21 CFR 182.3189retrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFA	Permitted, with conditions	12 food categories highest permitted level 200 mg/kg Show every food category 04.1.1.3 Peeled or cut fresh fruit — GMP 06.4.2 Dried pastas and noodles and like products — 200 mg/kg 08.1.2 Fresh meat, poultry and game, comminuted — GMP 09.1.2 Fresh molluscs, crustaceans, and echinoderms — GMP 09.2.1 Frozen fish, fish fillets, and fish products, including molluscs, crustaceans, and echinoderms — GMP 09.2.2 Frozen battered fish, fish fillets and fish products, including molluscs, crustaceans, and echinoderms — GMP 13.1.2 Follow-up formulae — 50 mg/kg 13.2 Complementary foods for infants and young children — 200 mg/kg 14.1.2.1 Fruit juice — GMP 14.1.2.3 Concentrates for fruit juice — GMP 14.1.3.1 Fruit nectar — GMP 14.1.3.3 Concentrates for fruit nectar — GMP	CXS 192-1995 Table Three, INS 302and 12 further provisionsretrieved 2026-09-07

Every name it appears under

28 recorded names. A label may use any of them.

E number

E302

INS number

CAS registry number

5743-27-1

As it appears in regulation

Calcium ascorbate

Other names

(R)-5-((S)-1,2-Dihydroxyethyl)-3,4-dihydroxyfuran-2(5H)-one calcium salt (2:1)
Ascorbic acid calcium
Ascorbic acid calcium salt
BLORRZQTHNGFTI-ZZMNMWMASA-L
Calci-C
Calcium ascorbate
Calcium ascorbate (e 302)
Calcium ascorbate anhydrous
Calcium ascorbate dihydrate
Calcium diascorbate
Calcium L-ascorbate
calcium;(2R)-2-[(1S)-1,2-dihydroxyethyl]-3-hydroxy-5-oxo-2H-furan-4-olate
CCRIS 7671
E 302
Ester-C
Hemicalcium ascorbate
HSDB 255
INS NO.302
INS-302
L-Ascorbic acid, calcium salt (2:1)
L-Ascorbic acid, calcium salt (2:1), dihydrate
Vitamin c (as calcium ascorbate)

Systematic names

Calcium bis{(2R)-2-[(1S)-1,2-dihydroxyethyl]-4-hydroxy-5-oxo-2,5-dihydrofuran-3-olate}
calcium;(2R)-2-[(1S)-1,2-dihydroxyethyl]-3-hydroxy-5-oxo-2H-furan-4-olate

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Calcium ascorbate

Where it is and isn’t permitted

What it is made from