As early as more than 80 years ago, people have mastered the method of producing monosodium glutamate. At that time, raw materials such as gluten and bean cake were mainly used, because there are many protein and protein in gluten, which are composed of more than 20 kinds of amino acids, including glutamic acid. Sodium glutamate (monosodium glutamate) can be obtained if glutamic acid is "pulled" out of protein macromolecules with chemicals such as hydrochloric acid and neutralized with alkali. This method is called hydrolysis.

Later, chemists invented a new method to produce glutamic acid by microbial fermentation with starch, sugar and nitrogen fertilizer as raw materials. This method is called fermentation. Microorganisms used for fermentation are "T-special bacteria" specially cultivated by scientists. Sugar and nitrogen fertilizer can be converted into glutamic acid under suitable conditions for their growth. Glutamic acid itself has a small solubility in water and a low umami taste, and it has a strong umami taste only after being neutralized into sodium salt. This is monosodium glutamate. Generally, monosodium glutamate often contains 20-40% salt, which can increase flavor.

Monosodium glutamate-sodium glutamate enters the stomach, and when it meets gastric acid, it will soon become glutamic acid easily absorbed by the human body. Glutamate is an expert in "grasping ammonia". Ammonia produced in human body may cause hepatic coma if it is not eliminated in time. Glutamate can "capture" excess ammonia in the body, so people will not get this disease. In addition, the brain is particularly sensitive to the presence of ammonia and needs glutamic acid to help.

Now, scientists have developed something fresher than monosodium glutamate, called "extra fresh monosodium glutamate", which is the essence of umami flavor. One of the substances called uric acid is 100 times fresher than monosodium glutamate.