"Monosodium glutamate can generally be produced by three methods: (1) hydrolysis of proteins
such as gluten or proteins present in sugar beet wastes, (2) synthesis, and (3) microbial fermentation. In the hydrolysis method, the protein is hydrolyzed with a strong mineral acid to free amino acids, and the glutamic acid is then separated from the mixture, purified, and converted to its monosodium salt, [monosodium glutamate].
" (Leung, A. and Foster, S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs , and Cosmetics. New York: Wiley, 1996. pp 373-375.)
While the glutamic acid in "monosodium glutamate" is generally produced through bacterial fermentation, the glutamic acid in the other MSG-containing ingredients is made through use of chemicals (hydrolysis or autolysis), enzymes (enzymolysis), fermentation, or a complex cooking process wherein reaction flavors are produced from a combination of specific amino acids, reducing sugars, animal or vegetable fats or oils, and optional ingredients including hydrolyzed vegetable protein.
In acid hydrolysis, crude gluten or other proteinaceous starting materials are generally hydrolyzed by heating with hydrochloric acid. The chemical hydrolysis with hydrochloric acid is said to be efficient, but almost any organic substance in the raw material is hydrolyzed, resulting in desired reactions such as hydrolysis of proteins, carbohydrates, fats (triglycerides), and the unwanted formation of mono and dichloro propanols, which are carcinogenic. The FDA has admitted, and even pretended to address the fact, that processed free glutamic acid created by acid hydrolysis contains carcinogenic mono and dichloro propanol ( Food Chemical News, December 2, 1996. Pp.24-25).