Acid-hydrolyzed vegetable protein, or HVP,[1] 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 vegetable based amino acids, glutamic acid. It is used as a flavor enhancer in many foods. Hydrolysis is a digestive process that occurs naturally in the human and animal stomach and as part of the kitchen cooking process.
Other sources of glutamate, sometimes used in conjunction with HVP, include autolyzed yeast extract and hydrolyzed yeast extract. Other vegetable sources are tomato and mushroom. A similar product, from dairy origin, is hydrolyzed whey protein.
Because of the high levels of glutamate in hydrolyzed vegetable protein, people sensitive to MSG should avoid hydrolyzed vegetable protein.[2]