E391

E391 is the European Union's E number designation for Magnesium hydroxide. Magnesium hydroxide is an inorganic compound with the chemical formula Mg(OH)2. It is a white solid that is sparingly soluble in water. In its natural form, it is found as the mineral brucite. Magnesium hydroxide is produced industrially by the reaction of magnesium oxide with water.

As a food additive, E391 is used primarily as an acidity regulator. This means it helps to control the pH of food products, preventing them from becoming too acidic or too alkaline. It can also function as an anti-caking agent, preventing powdered foods from clumping together. Additionally, it can serve as a coloring agent. E391 is permitted for use in a variety of food categories, including certain dairy products, baked goods, and confectionery. The acceptable daily intake (ADI) for magnesium hydroxide has been established by regulatory bodies. Its use in food is subject to specific regulations and maximum permitted levels to ensure consumer safety. Beyond food, magnesium hydroxide has various other applications, including in antacids, laxatives, and as a flame retardant.