E509

E509 is the European food additive code for magnesium chloride, a hygroscopic salt used by the food industry as a firming agent and coagulant. It is notably employed in tofu production, where magnesium chloride (nigari) coagulates soy milk to form curds. It is also used to help maintain texture in canned and pickled vegetables, contributing to crispness during processing and storage.

Chemistry and production: Magnesium chloride has the chemical formula MgCl2 and commonly exists as the hydrated hexahydrate MgCl2·6H2O. It is typically produced from brine processing and can be obtained as a by-product of potash or salt operations.

Regulatory status and usage: E509 is one of the EU-approved food additives, with purity criteria and usage limits defined by European food safety authorities. As an approved additive, it is permitted in specified product categories and within defined maximum concentrations to ensure safety and quality.

Safety and dietary considerations: When used within regulatory limits, magnesium chloride as E509 is considered safe for most consumers. As with other magnesium salts, high intakes can have laxative effects and may affect magnesium balance in sensitive individuals, such as those with kidney disease or severe magnesium deficiency. Proper labeling and adherence to permitted levels are required in food products containing E509.

See also: related E-number food additives and other chloride-based coagulants and firming agents.