|Picture 1.11a .A bottle of lemonade, showing the contents, including citric acid.|| |
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| || ||If the drink contains citric acid, then this is probably a microbial product. Most of the citric acid made today is produced by fermenting molasses or other sugar substrates with the mould Aspergillus niger. The strains of the fungus used in the commercial processes are a carefully kept secret! A high yield of citric acid can be achieved by controlling the conditions, such as sugar type and concentration, trace metal content, pH, aeration, phosphate concentration and the amount of ammonium salts. Up to 90% of glucose can be converted to citric acid in the process. |
Citric acid can be made by two different fermentation processes:
- the surface process
- the submerged process.
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