In China, MSG was once an indispensable condiment in people's lives, and no matter what you put on MSG, it will be much more flavorful. However, from the 1980s onwards, a variety of controversies about MSG more than up, there are rumors that MSG is toxic, and said that its inventor Japan has banned the consumption of MSG, there are also said that the temperature of more than 100 ℃, MSG will produce carcinogenic substances? monosodium pyroglutamate. These remarks once gave Chinese cuisine, which is used to being flavored with MSG, a cold shoulder internationally. Gradually, the people of China also have a prejudice against MSG, MSG can be eaten or not? Is it safe? Even if MSG is safe, are there any contraindications when using it? These questions exist in the minds of many people.

Circulating in the circle of friends, an article titled "these five dishes can not put MSG, unless you want to poison who! The article said that as long as the temperature exceeds 100 ℃, MSG will be denatured. Not only will it lose its fresh flavor, but it will also form toxic monosodium pyroglutamate.

Below, we will answer one by one.

First, what is MSG? What kind of origin does it have?

The main ingredient of MSG is monosodium glutamate, the sodium salt of glutamic acid, the molecular formula is , monosodium glutamate hydrolyzed to glutamic acid, and glutamic acid has a fresh flavor, which is the reason why MSG can be fresh. German Riederhausen first isolated monosodium glutamate in the process of protein hydrolysis. 1908, the Japanese chemist Ikeda Kikumiai extracted monosodium glutamate from kelp, and the next year, Suzuki Saburosuke commercialized it and named it ? Ajinomoto? , began to sell, which is the most primitive MSG.

In the beginning, gluten was used as a raw material and hydrochloric acid was added to hydrolyze to produce MSG, and in the 1950s, a Japanese man, Jiro Kinoshita, used the fermentation method to produce MSG. Later, the fermentation method came to the forefront, replacing the hydrolysis method, but the composition of the MSG produced by the two methods is the same. Overseas countries generally use sugar and honey as raw materials, while China uses grain crops, such as rice or corn, to produce MSG. The monosodium glutamate content of MSG on the market is 99%, 80% and 60% in several different types.

Monosodium glutamate is found in fruits like grapes and tomatoes, and since grapes and tomatoes are harmless, MSG is also edible, right? As for the hydrolyzed glutamate is also a nutrient needed by the human body, life in many animal and plant protein foods contain glutamate, such as milk, eggs, pork, etc.? MSG is toxic? The theory is not attacked from the beginning.

From the molecular formula of monosodium glutamate, it can be seen that it is a kind of unstable state, it is very easy to dehydrate after heating into another stable substance? Monosodium pyroglutamate. But first of all, the temperature is not the rumored 100 ℃, MSG dissolves the best temperature is 70 ℃ -90 ℃; at 150 ℃, it will be dehydrated, resulting in crystallization; if to 200 ℃ or more, monosodium glutamate will occur within the molecular dehydration, which becomes pyroglutamic acid. Secondly, since pyroglutamic acid has no fresh flavor, ? The conversion of monosodium glutamate to monosodium pyroglutamate reduces the fresh flavor? is correct, but the statement that pyroglutamic acid causes cancer has not been scientifically proven. Sodium pyroglutamate alias L-2-pyrrolidone-5-carboxylic acid sodium, molecular formula for C5H8NO4Na?H2O. it is also a white crystalline powder, very soluble in water, a weak irritation, but no allergic reaction, the use of the basically non-toxic, harmless to the human body.

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According to a CCTV survey, more than half of consumers are resistant to MSG.

So, from a scientific point of view, the so-called ? The MSG cancer theory? More alarmist talk. It is worth noting that usually in the use of MSG, taking into account the molecular characteristics of monosodium glutamate, acidic and alkaline dishes are not easy to add MSG flavoring. In the monosodium glutamate salt only L-type with fresh flavor, its aqueous solution has a more pure fresh flavor, therefore, in a slightly acidic aqueous solution, PH value of 5.5-8.0, the strongest fresh flavor; and PH value less than 4, the fresh flavor is weak; PH value greater than 8 will form disodium salts, which will be the disappearance of the fresh flavor.

From the point of view of taste, add MSG should also pay attention to the temperature, 70 ℃ -90 ℃ is the most appropriate. Stir-fried dishes are generally added before the dishes out of the pot, in order to prevent dehydration to generate monosodium pyroglutamate, the loss of fresh flavor; and cold dishes to be put early, so that it is fully dissolved.

In addition, the appropriate concentration of monosodium glutamate (MSG) is 0.2% -0.5%, so add the time to pay attention to the right amount, one is not to suppress the flavor of the dishes, and the second is not too late, too much intake of MSG on the body is not beneficial, the reason is the same as salt, MSG contains sodium, hypertension patients should not be eaten more.

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References:

"Talking about monosodium glutamate (MSG)", Liu Chengqi and Liu Xiaoxia, Journal of Xinzhou Normal College, 1999-11-15;

"Monosodium pyroglutamate and brain memory and cognitive function", Lou Xiuyu and Zhu Hongqing, China Science and Technology Information, 2012-01-15.< /p>

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Written by Zhang Lianmin