Chemistry of ascorbic acid The main use of -ascorbic acid and its salts is as food additives, mostly to combat oxidation. It is approved for this purpose in the EU with E number E300, USA, Australia, and New Zealand) Another major use of -ascorbic acid is as dietary supplement. Natural biosynthesis of vitamin C occurs in many plants, and animals, by a variety of processes. Eighty percent of the world's supply of ascorbic acid is produced in China. Ascorbic acid is prepared in industry from glucose in a method based on the historical Reichstein process. In the first of a five-step process, glucose is
Vitamin C -Galactose reacts with the enzyme -galactose dehydrogenase, whereby the lactone ring opens and forms again but with between the carbonyl on C1 and hydroxyl group on the C4, resulting in -galactonolactone. -Galactonolactone then reacts with the mitochondrial flavoenzyme -galactonolactone dehydrogenase. to produce ascorbic acid. -Ascorbic acid has a negative feedback on -galactose dehydrogenase in spinach. Ascorbic acid efflux by embryo of dicots plants is a well-established mechanism of iron reduction, and a step obligatory for iron uptake. All plants synthesize ascorbic acid. Ascorbic acid functions as a cofactor for enzymes involved in photosynthesis, synthesis of plant hormones, as an antioxidant