Overview

Monosodium glutamate (MSG) is the sodium salt of glutamic acid, an amino acid found throughout nature. In cooking and the food industry it is valued as a flavor enhancer because it accentuates savory, or umami, taste sensations without adding sweetness or sourness. MSG appears as a white crystalline powder that dissolves in water and is used in small amounts to boost perceived depth and meatiness in many dishes.

Occurrence and production

Free glutamate — the form that produces umami — exists naturally in a wide range of foods. Higher concentrations are found in protein-rich items such as meats and aged products, and specifically in many protein-containing foods. Common examples include meat, fish and dairy, as well as tomatoes, mushrooms and certain seaweeds. Commercial MSG is most often manufactured by microbial fermentation of carbohydrates, a process similar to the production of many amino acids and fermented food ingredients. It is identified in international food regulation by the E number 621.

History

The flavor now called umami was described in the early 20th century and isolated by Japanese chemist Kikunae Ikeda, who recognized glutamate as its key component and developed a method to produce MSG as a seasoning. Since then MSG has been incorporated into cuisines and industrial food production around the world, both as a stand-alone seasoning and as an additive in stocks, sauces, soups and processed foods.

Uses and examples

MSG is used to intensify savory notes and to reduce the need for added salt in some preparations. Typical applications include broths and soups, seasoning blends, snack foods, canned and frozen meals, marinades and restaurant kitchens. Home cooks sometimes add a small pinch of MSG to stir-fries, stews or sauces to deepen flavor without overt salting.

Safety, regulation and misconceptions

Regulatory authorities treat MSG as a permitted food additive. In the United States the Food and Drug Administration considers MSG generally recognized as safe and requires that added MSG be listed on ingredient labels. It is also categorized as a food additive in many jurisdictions. During the late 20th century reports of transient symptoms after consuming large amounts of MSG gave rise to the term often called "Chinese restaurant syndrome;" subsequent research has not established a consistent causal relationship for most people. Some individuals report mild, short-lived reactions if they consume MSG in large quantities on an empty stomach, but broad-based scientific reviews find no clear evidence of serious or long-term harm from normal culinary use.

Distinctions and notable facts

  • Free glutamate (as in MSG or ripe tomatoes) produces umami, while bound glutamate within intact proteins does not taste the same until proteins are broken down.
  • MSG supplies flavor without contributing the same sodium burden as an equivalent amount of table salt by weight for similar flavor effects, so it can be used to reduce overall salt in some recipes.
  • Because glutamate is a common constituent of many natural foods, MSG is often described as concentrating a naturally occurring flavor rather than creating an unnatural taste.

For further reading on the chemistry of glutamate, industrial methods, and regulatory summaries, see resources linked above and food-safety guidance from national health authorities.