Processed free glutamic acid (MSG) is different. MSG used in food, dietary supplements, cosmetics, pharmaceuticals, and vaccines is produced commercially in manufacturing and/or chemical plants, and/or by fermentation. The glutamate in plant and animal protein is L-glutamate only. The glutamate in MSG contains D-glutamate as well as L-glutamate.
There are six basic methods for producing MSG. Glutamate can be freed from protein through autolysis, acid hydrolysis, enzymolysis (hydrolysis using enzymes), and/or fermentation of protein (2-4). Glutamate can also be produced by combining specific amino acids, reducing sugars, animal or vegetable fats or oils, and optional ingredients including hydrolyzed vegetable protein (5,13). Its products are often referred to as "processed flavors" or "reaction flavors."
These first five methods for producing MSG all produce processed free glutamic acid (MSG) in combination with other amino acids. Processed free glutamic acid (MSG) can also be produced as a single amino acid using bacterial fermentation, a process whereby carefully selected genetically modified bacteria secrete free glutamic acid through their cell walls (6).
Today, this method of bacterial fermentation is used to produce much, if not all, of the free glutamic acid used by the pharmaceutical industry. It is also used to produce the food ingredient monosodium glutamate.
For information about carcinogenic propanols access:
The National Toxicology Program (NTP) of the National Institute of Environmental Health Sciences (NIEHS) at the National Institutes of Health (NIH) Review of Toxicological Literature, and The Codex Alimentarius Commission Position Paper on Chloropropanols.
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3. Ajinomoto Co., Inc.Monosodium Glutamate (MSG). In: Hui YH, ed. Encyclopedia of food science and technology, Vol 3. New York: Wiley, 1991: 1833-1836.
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5. Lin LJ. Regulatory status of maillard reactions flavors, Washington DC: Division of Food and Color Additives, Center for Food Safety and Applied Nutrition, Food and Drug Administration. Paper presented at a meeting of the American Chemical Society, August 24, 1992.
6. Leung A, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics. New York: Wiley, 1996: 373-375.
7. Deki M, Echizen A, Temma T. Minor components in monosodium glutamate. Kanzei Chuo Bunsekishoho.1977;17:59-62.
8. Man EH, Bada JL. Dietary D-Amino Acids. Ann Rev Nutr.1987;7:209-225.
9. Konno R, Oowada T, Ozaki A, Iida T, Niwa A, Yasumura Y, Mizutani T. Origin of D-alanine present in urine of mutant mice lacking D-amino-acid oxidase activity. Am J Physiol. 1993;265:G699-G703.
10. Sjostrom LB. Flavor potentiators. In: Furia TE, CRC Handbook of Food Additives. Cleveland: CRC Press, 1972: 513-521.
11. Rundlett KL, Armstrong DW. Evaluation of free D-glutamate in processed foods. Chirality. 1994;6:277-282.
12. Food Chemical News, Dec 2, 1996. p24-25.
13. Food Chemical News, May 31, 1993. p16.