Erythorbic acid (isoascorbic acid,
D-araboascorbic acid) is a
stereoisomer
In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in ...
of
ascorbic acid (
vitamin C
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) ...
). It is synthesized by a reaction between methyl 2-keto-
D-gluconate and
sodium methoxide
Sodium methoxide is the simplest sodium alkoxide. With the formula , it is a white solid, which is formed by the deprotonation of methanol. Itis a widely used reagent in industry and the laboratory. It is also a dangerously caustic base.
P ...
. It can also be synthesized from
sucrose or by strains of ''
Penicillium
''Penicillium'' () is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production.
Some members of the genus produce pe ...
'' that have been selected for this feature. It is denoted by
E number E315, and is widely used as an
antioxidant in processed foods.
Clinical trials have been conducted to investigate aspects of the nutritional value of erythorbic acid. One such trial investigated the effects of erythorbic acid on vitamin C metabolism in young women; no effect on vitamin C uptake or clearance from the body was found. A later study found that erythorbic acid is a potent enhancer of nonheme-iron
absorption.
Since the U.S. Food and Drug Administration banned the use of
sulfites as a
preservative
A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by ...
in foods intended to be eaten fresh (such as salad bar ingredients), the use of erythorbic acid as a food preservative has increased.
It is also used as a preservative in cured meats and frozen vegetables.
It was first synthesized in 1933 by the German chemists Kurt Maurer and Bruno Schiedt.
[See also:
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References
{{reflist
Food antioxidants
E-number additives
Substances discovered in the 1930s