INS 330 is citric acid, the acid that gives lemons and limes their sharp taste, numbered E330 in Europe. Codex lists it as an acidity regulator, antioxidant, colour retention agent and sequestrant, which makes it one of the most widely used food additives.
Although it occurs naturally in citrus fruit, almost all citric acid used in food today is made by fermentation: the mould Aspergillus niger is grown on sugar or starch syrups, and the acid is then purified and crystallised.
In snacks it does several jobs. It adds the tang to flavours such as Lay’s Chili Lime and to gummies like Jolly Bears, balances sweetness in fruit fillings and creams, and, by binding traces of metals, helps slow the oxidation that makes fats taste stale.
