Many tens of thousands of tons of vitamin C are produced synthetically each year from glucose; the initial stages in conversion involve reduction to sorbitol followed by bacterial oxidation to sorbose. Much of this vitamin C finds its way into health-food stores for sale to megatherapy enthusiasts as a putative dietary adjuvant. A substantial proportion is used industrially as a “technological aid”; some is used in meat-curing processes to promote pigment conversion (in this application, it also has an adventitious and unintended role in reducing the formation of volatile N-nitrosamines).
Vitamin C is also widely employed as a permitted antioxidant (sometimes as ascorbyl palmitate) to prevent the formation of rancidity in stored fat products and the phenolic browning of commodities such as dehydrated potatoes. It is used as a flour improver in the Chorleywood Bread Process, where its oxidation product (dehydroascorbic acid) modifies the availability of glutathione in dough development, thereby shortening the period of fermentation.
The use of vitamin C in these technological processes finds general approval on the grounds that one is, after all, adding a beneficial vitamin rather than some untried additive of unknown toxicity. It should be pointed out, though, that little of this additive vitamin C is recoverable from the marketed product, which will, however, contain substantial amounts of vitamin C breakdown products - many of them unidentified and almost all of them of unknown toxicity. Bread is vitamin C-free despite the substantial amounts that may have been added during the Chor-leywood process. It has been estimated that the average consumer may ingest up to 200 mg a week of vitamin C breakdown products from additive sources (Thomas and Hughes 1985).
World History
