Umami in Japanese means something delicious. In Japan, umami is the taste sensation produced by monosodium glutamate (glutamic acid or MSG). It is the famous 5th taste, the least known of the others: salty, sweet, sour, and bitter. At the beginning of the last century (in 1908), Kikunae Ikeda, a chemistry professor at Tokyo Imperial University, succeeded in synthesizing MSG from kombu seaweed. It is used as a flavor enhancer, both in its synthesized version in the form of elongated crystals and in ingredients in which it is widely present (e.g., soy sauce and fish sauce).
A few years later, a colleague of Ikeda’s discovered that another substance also produces the sensation of umami: IMD, or inosine monophosphate. Then, in 1960, Akira Kuninaka found another meaning in shitake mushrooms called GMP or guanosine monophosphate, which also provides umami.
It was later discovered that these three substances are synergistic, i.e., tiny amounts of each contribute to increasing umami’s sensation. MSG is currently produced in large quantities using a bacterium that synthesizes it.
In 2001, biologist Charles Zuker of the University of California found specific taste receptors for umami on humans and other animals’ tongues.
In addition to perception through taste receptors, MSG also has effects that I believe may contribute to increasing the pleasurable perception of foods containing it:
On the one hand, it increases salivation, which makes the ingredients more intensely perceived.
This increase in salivation probably occurs as a defense against acids (glutamic acid) since saliva, being alkaline, counteracts the acidity to prevent tooth enamel deterioration.
On the other hand, it generates a physiological sensation very similar to the one that occurs when we take something we love. Some people think it can contribute to us feeling that what we are eating is delicious. It is close to our mouths’ physiological reaction with foods that we love when we know that this is happening. We tend to think that what we take is delicious.
It is naturally present in countless foods: aged cheeses (especially Parmesan), Serrano ham, salted anchovies, soy sauce and fish sauces from Southeast Asia, kombu seaweed, umami mushroom, asparagus, tomatoes, and many ripe fruits.
Many people like to use it with ingredients that naturally contain this flavor so that the sensation it produces is not inconsistent with what we are used to feeling with those products. For example, you can add umami mushroom to many dishes; this improves incredibly, especially if you use tomatoes that are not fully ripe.
There are several opinions that associate glutamate or glutamic acid with sound health effects: its use makes it possible to reduce the amount of salt in food without reducing the perception of saltiness that we like so much in food enhances the perception of salty taste and vice versa. It is a product that is not harmful, even in large quantities.
As for the quantities to use, I recommend using it in the same proportions as salt, always bearing in mind that in large quantities it produces an unpleasant taste and a strange sensation in the back of the mouth that can ruin the dish. Always keep in mind that the amounts depend on the umami content of the product with which you will use it, and that salt increases the perception of umami.