Ascorbic Acid (Vitamin C)

How it's made

Made by fermentation/synthesis from glucose.

Ascorbic acid is simply vitamin C, used in food not only for nutrition but as one of the most important antioxidants: it protects colour and flavour from oxidation, stops cut fruit and vegetables browning, helps preserve cured meats, and improves bread dough. The additive and the vitamin are the same molecule.

Industrial ascorbic acid is made from glucose through a multi-step process. The long-established Reichstein process combines chemical steps with a single bacterial fermentation that converts sorbitol to sorbose; a more modern two-step fermentation route uses microbes for more of the sequence. Either way, glucose (usually from corn) is transformed through a series of controlled reactions into ascorbic acid.

The finished acid is crystallised and purified to a highly pure white powder identical to natural vitamin C. Although the process may begin with corn-derived glucose, the end product is a single pure chemical containing none of the original plant protein, which is why it suits people with corn allergies and is used in vast quantities across the food industry.