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What is MSG, and is it Actually Made from Seaweed?

By August 19, 2022October 6th, 2022MSG
what is msg

Readers of MSGdish are familiar with the story of how MSG was discovered.

As history tells us, over a 100 years ago a Japanese scientist and professor named Kikunae Ikeda was intrigued with the savory, fulsome flavors of the broth called dashi, a savory stock made from a fermented base of boiled dried seaweed and dried fish.

Dashi is important in making the flavors of miso soup, ramen and soba dipping sauces that taste so distinctly Japanese.1

Dr. Ikeda set about to find the source of the rich flavor in dashi. Using dried seaweed (kombu, also spelled as konbu), he conducted a series of experiments. Evaporation and treatment of the seaweed resulted in a white crystalline substance with a molecular formula the same as glutamic acid, an amino acid commonly present in all living organisms, and in all animal and plant sources of protein. In the body, glutamic acid is often found as glutamate, where it performs many vital functions.2

Ikeda had identified the savory flavor source of dashi. The glutamate crystals tasted of the same familiar distinct flavor found in dashi. Ikeda named the flavor “umami” from the Japanese for “delicious.” Umami is now recognized as one of the five basic tastes, along with sweet, salty, bitter and sour.

Ikeda conducted experiments to develop the best medium for glutamate to deliver the umami taste. He found that MSG (monosodium glutamate), a combination of sodium and glutamate, was the best flavoring as it was readily soluble in water, had a strong umami taste, high stability and absorbed no humidity.

In 1908, Ikeda started manufacturing MSG under the name Ajinomoto (meaning “essence of taste”). He produced glutamate not by seaweed however, but by using fermented vegetable proteins. MSG became a staple in Asian cuisine, widely popular for its ability to deliver umami flavor, and also to enhance the original flavors of foods. So important was the contribution of Ikeda, that the Japanese Government Patent Office named him one of the ten greatest Japanese inventors.3

how is MSG madeToday, instead of extracting and crystallizing glutamate from seaweed broth like the original discovery, it is produced by the fermentation of plant-based ingredients such as sugar beets, sugar cane or corn. This fermentation process is similar to that used to make yogurt, vinegar and wine. The glutamate produced is chemically indistinguishable from the glutamate naturally found in food proteins and the body metabolizes both sources of glutamate in the same way.

Seaweed (nori or edible seaweed sheets) has been prized in Japan since ancient times for its flavor and flavor enhancing properties. Nori is now commonly made from edible red algae. It has become popular in the west, often found in markets in small mini-sheets sized for snacking and larger sized sheets for making sushi. The glutamate content of nori is abundant at 1378 mg/100 grams, giving it an umami explosion of flavor.

If you would like to see what nori can do to enhance the flavors of your food, try toasting nori sheets until crisp, and then sprinkle on rice bowls, noodles or salads. Top avocados, cucumber or scrambled eggs with crumbled nori for an umami burst of flavor.4 Nori mayonnaise can be used as a dip, on crackers with smoked fish, over hard-boiled eggs or slathered on your sandwich. And if you don’t have nori readily at hand, a sprinkle of MSG will deliver the same great umami flavor (which is why MSG is often referred to as “umami seasoning”).

Toasting Nori Sheets

  • Preheat oven to 350 degrees F. Place nori sheets in a single layer on a baking sheet (I find lining the baking sheet with parchment paper helpful to prevent sticking).
  • Use a brush to lightly wet the surface of each sheet with water.
  • Toast in the oven until just crisp.

Toasted Nori Mayonnaise 5

Makes about 1 cup


  • 3 toasted nori sheets, chopped
  • 1 cup mayonnaise
  • 2 teaspoons fresh lime juice
  • Kosher salt


  • Finely grind nori in a spice mill or a blender. Mix nori, mayonnaise, and lime juice in a small bowl; season with salt.
  • Do Ahead: Mayonnaise can be made 5 days ahead. Cover and chill.



  1. Ang Rosalind. Michelin Magazine. A Guide to Dashi, The Soul of Japanese Food. July 6, 2018.
  2. Geiling Natasha. It’s the Umami, Stupid. Why the Truth About MSG is So Easy to Swallow. Smithsonian Magazine. November 8, 2013. 
  3. Ninomiya K, Rozin E. The Fifth Taste of Human Beings. Umami the World. Umami Information Center. Cross Media Limited. 2007.
  4. Nava A. A Guide to Nori-with 11 recipes that aren’t sushi. The Vegan Atlas. August 19, 2020.
  5. Saffitz C. Toasted Nori Mayonnaise. Bon Appétit. December 15, 2015.

Mary Lee Chin is a registered dietitian specializing in health communications. Committed to providing the public with sound nutrition information, she is regularly consulted by local and national media on nutrition trends and significant health and food issues. Her company, Nutrition Edge Communications, specializes in translating peer-reviewed research into realistic and practical recommendations, and countering myths and misinformation. Mary Lee was recently awarded Outstanding Dietitian of the Year by the Colorado Dietetic Association. Read more about her background on the About page. Note: MSGdish bloggers are compensated for their time in writing for MSGdish, but their statements and opinions are their own. They have pledged to blog with integrity, asserting that the trust of their readers and their peers is vitally important to them.

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