Chemical Properties
Erythorbic acid occurs as a white or slightly yellow-colored crystals
or powder. It gradually darkens in color upon exposure to light.
Definition
ChEBI: D-isoascorbic acid is an ascorbic acid.
Production Methods
Erythorbic acid is synthesized by the reaction between methyl 2-
keto-D-gluconate and sodium methoxide. It can also be synthesized
from sucrose, and produced from Penicillium spp.
Biotechnological Production
Yeasts and other fungi synthesize the C5 sugar acid D-erythroascorbic acid which
shares structural and physicochemical properties with Asc. D-erythroascorbic
acid serves similar protective functions in these microorganisms as Asc does in plants
and animals, including the scavenging of reactive oxygen species. The biosynthesis
of D-erythroascorbic acid starts from D-arabinose obtained by the microorganism
from decaying plant material. D-arabinose, presumably in its
1,4-furanosidic isomeric form, is oxidized by NAD(P)+ specific dehydrogenases
to D-arabinono-1,4-lactone, which is further oxidized to D-erythroascorbic
acid by D-arabinono-1,4-lactone oxidase. Resting cells of Saccharomyces
cerevisiae can synthesize Asc from L-galactose, L-galactono-1,4-lactone, or L-gulono-
1,4-lactone via the pathway naturally used for D-erythroascorbic acid.
Flammability and Explosibility
Nonflammable
Pharmaceutical Applications
Erythorbic acid is a stereoisomer of L-ascorbic acid, and is used as
an antioxidant in foods and oral pharmaceutical formulations. It
has approximately 5% of the vitamin C activity of L-ascorbic acid.
Safety
Erythorbic acid is widely used in food applications as an
antioxidant. It is also used in oral pharmaceutical applications as
an antioxidant. Erythorbic acid is generally regarded as nontoxic
and nonirritant when used as an excipient. Erythorbic acid is readily
metabolized and does not affect the urinary excretion of ascorbic
acid.
The WHO has set an acceptable daily intake of erythorbic acid
and its sodium salt in foods at up to 5 mg/kg body-weight.
Solubility in organics
40% soluble in water. Soluble in alcohol, slightly soluble in Glycerin and Propylene
glycol.
storage
Erythorbic acid should be stored in an airtight container, protected
from light, in a cool, dry place.
Purification Methods
Crystallise D(-)-isoascorbic acid from H2O, EtOH or dioxane. is at 245nm with 7,500 (EtOH). [Reichstein et al. Helv max Chim Acta 17 510, 516 1934, Heslop et al. J Chem Soc 225 1944, Beilstein 18 III/IV 3037, 18/5 V 26.]
Incompatibilities
Erythorbic acid is incompatible with chemically active metals such
as aluminum, copper, magnesium, and zinc. It is also incompatible
with strong bases and strong oxidizing agents.
Regulatory Status
GRAS listed. Accepted for use as a food additive in Europe.
Included in the FDA Inactive Ingredients Database (oral concentrate
and tablets).
