A Taste Sensation

Amy Leyva

Historically one of the most reviled of food additives, monosodium glutamate (MSG) is used around the globe as a flavor enhancer—at the table, in the kitchen, and in industrial food processing plants. The glutamate burst that it produces occurs naturally in high concentrations in many commonly consumed foods, including tomatoes, Parmesan cheese, and dried mushrooms. As an additive, MSG is used in processed broths and seasonings, in chips and other popular snack foods, and, quite possibly, in the kitchen of your favorite Chinese restaurant.

In recent decades MSG has become the culinary foe of conscientious consumers because of the supposed “Chinese restaurant syndrome,” a complex of symptoms that includes headache, shortness of breath, and chest pain and that may or may not be a result of ingesting too much of the flavoring. To elude the stigma of this malady manufacturers often mask MSG in food labels and ingredient lists. It goes instead by a number of alternate compound names and trademarks, including yeast extract, hydrolyzed vegetable protein, sodium caseinate, Ac’cent, Vegemite, Marmite, Maggi, Sazón Goya, and Ajinomoto, the first name under which MSG was manufactured and sold as a flavor enhancer. While “monosodium glutamate” may spell pariah to consumers, by any other name this compound continues to thrive in its 100th year of existence.

In 1908 Kikunae Ikeda, a Japanese chemist at Tokyo Imperial University (now the University of Tokyo), identified a fifth taste quality, separate from the known tastes of sweet, sour, bitter, and salty. Ikeda perceived this taste when he ate fish, meat, and the dashi (a dried seaweed broth) that he frequently dined on. He introduced the term umami in a 1909 article to describe this taste category; it has since been translated into English as “deliciousness” and “savoriness.” (Ikeda’s dabbling in neuroscience would be scientifically validated 87 years later, when researchers at the University of Miami identified the glutamate taste receptor.)

Ikeda pursued his hunch about the umami flavor in seaweed and found that it came from glutamic acid, an amino acid identified in 1866 by German chemist Karl Ritthausen. Ikeda proceeded to separate the salts of the acid, thus isolating glutamate for the first time. After taking a bite of a cluster of the resulting crystals he reported a clear perception of the umami taste he was seeking.

Ikeda patented his production method right away and began manufacturing MSG in 1909. He marketed it as a flavor enhancer under the name Ajinomoto (from the Japanese phrase aji no moto, “essence of taste”). The flavoring hit American shores in 1947 with the trade name Ac’cent. As the process of extracting the compound from seaweed soon proved inefficient and costly for large-scale manufacture, Ikeda developed a more profitable alternative of fermenting molasses and wheat; fermentation of various starches remains the choice of MSG producers today. The Ajinomoto Corporation, still the world’s largest producer, manufactures 1.5 million tons annually.

All of that MSG has to go somewhere. MSG continues to bear a seemingly unfair reputation among the American public despite a century of use and the well-researched conclusion by the Food and Drug Administration and World Health Organization that it presents no known health risk. But all over the world, sometimes under clever cover, it is savored with delight.

Amy Leyva is the production editor of Chemical Heritage.