Acid-hydrolyzed vegetable protein, or HVP, is produced by boiling cereals or legumes, such as soy, corn, or wheat, in hydrochloric acid and then neutralizing the solution with sodium hydroxide. The acid hydrolyzes, or breaks down, the protein in vegetables into their component amino acids. The resulting dark coloured liquid contains, among other amino acids, glutamic acid, which consumers are more familiar with in the form of its sodium salt, monosodium glutamate, or MSG.