1908 One day, Mr. Ikeda Miaoju, a professor in the Department of Chemistry at the University of Tokyo, Japan, was having dinner, and the soup made by his wife was particularly delicious. He was surprised to ask his wife what soup it was, and the answer was kelp and cucumber soup. Keen Ikeda guessed that it must be caused by something contained in kelp. Before he finished eating, he took the remaining kelp into the laboratory. After repeated chemical analysis, he found that kelp contains a substance called sodium glutamate, which makes the soup delicious. After more than a year of unremitting efforts, he extracted sodium glutamate and obtained a patent. Later, Professor Ikeda prepared sodium glutamate from wheat and soybean and put it into industrial production. He officially introduced a product called "Flavor Essence" to the market, which quickly became popular in Japan and even the world.
At the beginning of the 20th century, Japanese advertisements of "essence" were widely seen in many places in China. At that time, Wu, a chemical engineer in China, became very interested in this white powder. He bought a bottle of analysis and learned that its chemical composition was sodium glutamate, so he made up his mind to make China's own taste. With tenacious perseverance and knowledge, after more than a year of experiments, he extracted10g white powder crystal, which tasted the same as Nissan's and was successful. Inspired by the names of "perfume essence" and "saccharin" at that time, Wu named this very fresh substance "monosodium glutamate", and from then on, China also had domestic flavor elements. MSG is delicious. Wu described that only chefs in the sky can make it, so he named the factory that produced MSG with Zhang Chongxin as "Chutian MSG Factory". The factory was built in 1923, producing "bergamot" monosodium glutamate. "Chutian" and "bergamot" are very harmonious. The advertising words of the product are short and pithy, which are quite distinctive, such as "Tianjiu monosodium glutamate is delicious", "pure texture, necessary for kitchen" and "completely made in China". The monosodium glutamate business started at once and sold all over the country for a long time. 1939 monosodium glutamate factory was built in Hong Kong. "Bergamot" monosodium glutamate dares to compete with Japanese products, not only selling well in Southeast Asian countries, but also entering the American market. Wu, who became a chemical industrialist, won the title of "King of Monosodium Glutamate" and won a sigh of relief for the national industry and commerce in old China.
Monosodium glutamate, also known as monosodium glutamate, is the monosodium salt of L- glutamic acid (molecular formula C5H8NO4Na), which is white crystal or crystalline powder, contains one molecule of crystal water, is odorless, easily soluble in water, slightly soluble in ethanol, has no hygroscopicity, is stable to light, does not decompose when heated under neutral conditions, and is generally non-toxic; It is the main component of commercial monosodium glutamate and also used as medicine. An injection made of sodium glutamate is clinically used for intravenous drip to treat hepatic coma and mental symptoms caused by blood ammonia.
As a seasoning, monosodium glutamate is a dry granule or powder, which is slightly hygroscopic because it contains a certain amount of salt, so it should be sealed against moisture. The contents of sodium glutamate in monosodium glutamate are 90%, 80%, 70% and 60% respectively, of which 80% is the most common, and the rest is refined salt, which acts as a filler to keep fresh. There is also salt-free "crystal monosodium glutamate" with larger particles on the market.
The dosage of monosodium glutamate in cooking should be appropriate, and the general concentration should not exceed five thousandths. Too much is stale. Monosodium glutamate is slightly alkaline, so it is not suitable for use under alkaline conditions. It will produce salty but not salty and astringent disodium glutamate, and its flavor will be reduced. MSG is also not suitable for use at high temperature. Crystalline water will be lost at 150℃, and pyrrolidone will generate harmful pyroglutamic acid at 2 10℃, which will decompose when it reaches the melting point of 270℃. When heated under acidic or alkaline conditions with pH less than 5, monosodium glutamate will also produce pyrrolidone, which will reduce its freshness. The suitable temperature of monosodium glutamate is about 80℃, and the highest temperature is not more than 120℃. It should be used under weak acid or neutral conditions, and it is usually added before eating, which has the best effect.
Monosodium glutamate can be absorbed, enter the body, participate in the synthesis of protein needed by human body, stimulate appetite and promote digestion, but it is not advisable to eat more, and the daily intake per person should not exceed 6g. Excessive consumption will increase the content of glutamic acid in blood, affect the utilization of divalent calcium and magnesium cations necessary for metabolism, and cause symptoms such as headache, heartbeat and nausea for a short time. Babies should eat less.
The early production of monosodium glutamate was realized by protein hydrolysis. Make flour into gluten containing more protein, or heat it with bean cake and hydrochloric acid solution to completely hydrolyze protein into a solution containing glutamic acid, and then concentrate and crystallize. Glutamic acid itself is slightly acidic and has little flavor, so it must be made into sodium salt to improve freshness. Dissolve crude glutamic acid crystal in water, then neutralize it with alkali to form sodium salt, remove impurities such as pigment with activated carbon, and then concentrate and crystallize to obtain sodium glutamate with purity over 99%. Every 100 kg of flour can get 5 ~ 6 kg of products. The monosodium glutamate hydrolysis method has low utilization rate of grain, poor working environment and serious corrosion of equipment, and will be phased out in the future.
Since 1950s, people have used sugar and nitrogen fertilizer (ammonium sulfate, ammonia water, urea, etc. ) as raw material, glutamic acid is produced by mycophenol. This method is sanitary and economical, and it can produce more than 50 kilograms of glutamic acid per 100 kilograms of sugar, so it has been rapidly popularized as the main method for producing monosodium glutamate at present. In the production process, sugar, nutrients, urea, etc. Mixing into culture solution, sterilizing with high-temperature steam, cooling, and inoculating pure bacteria (including micrococcus, Bacillus, actinomycetes, Bacillus, etc.). ). Under the suitable conditions of artificial control, use an air compressor to blow sterile air into the culture solution, and keep stirring to make bacteria multiply. Bacteria first convert sugar into ketoglutaric acid (C5H6O5), and then through the action of enzymes in bacteria, ketoglutaric acid combines with ammonia to produce glutamic acid (C5H9O4N). Bacteria can convert most sugar and urea into glutamic acid. The fermentation broth containing glutamic acid is filtered and sterilized, then hydrochloric acid is added to precipitate it, and then purified glutamic acid can be obtained by recrystallization, which can be used to produce monosodium glutamate. Fermentation can also make comprehensive use of waste molasses left over from sugar industry. For example, the molasses of beet sugar can produce about 23 kg monosodium glutamate per 100 kg.
As we all know, the dishes made of chicken, duck and fish are delicious, because they are rich in protein. Protein is made up of various amino acids (general formula H2N R COOH), many of which are delicious. After the meat is cooked, protein is decomposed into various amino acids, which is the source of umami flavor. Protein content in vegetables is low, so vegetable soup is naturally not as fresh as meat and fish soup. Crab, snail and clam soup are relatively fresh because they contain sodium succinate (sodium succinate C4H4Na2O4).
Soy sauce in condiments is fresh because it contains amino acids such as glutamic acid, while monosodium glutamate is fresh because it is the sodium salt of glutamic acid. Although monosodium glutamate is fresh, there are buildings outside the mountain, and there are fresher substances than it. If the freshness of more than 99% sodium cereal is set as 100, then the freshness of inosine sodium can reach 4000, which is a flavor rising in the 1960s. Also called disodium inosine phosphate, the molecular formula is c10h1o8n4pna2, which contains 5 ~ 7.5 molecules of crystal water. It is gradually prepared by fermenting starch saccharification liquid with inosine bacteria. This colorless or white crystal is soluble in water, but insoluble in ethanol and ether. Its aqueous solution is stable to heat and has high safety. Its flavoring efficiency is more than 20 times that of monosodium glutamate, and it can be added to soy sauce and monosodium glutamate. The "strong monosodium glutamate" and "fresh monosodium glutamate" seen in the market are composed of 88-95% monosodium glutamate and 12-5% inosine sodium, and the freshness is above 130.
Mushrooms, shiitake mushrooms and other fungal plants are very delicious whether fried or made into soup. After the advent of monosodium glutamate at the beginning of this century, Japanese scientists have studied the causes of the delicious taste of mushrooms. After analysis, it contains a substance called "uric acid", which is fresher than Ajisen 100 times, and it was not made successfully at that time. Later, scientists extracted "sodium uridine" from shiitake mushrooms, and its freshness was as high as 16000. It was first made in Japan in the 1960s, so it was the first to introduce "the essence of special flavor" in the Japanese market. Sodium glucoside, also known as disodium glucoside phosphate, has a molecular formula of C 10H 12O8N5PNa2. White crystalline powder, containing 4 ~ 7 molecules of crystalline water, tasteless, soluble in water, insoluble in ethanol, ether and acetone. As a seasoning, it is several times fresher than inosine sodium, and has a strong mushroom flavor. Sodium oleate and proper amount of monosodium glutamate will have a "synergistic effect", which is 0/00 times fresher than ordinary monosodium glutamate. Adding a small amount of sodium oleate to ordinary monosodium glutamate will become "extra fresh monosodium glutamate", which also appeared in China's market in the early 1980s.
A few years ago, people made a new super-fresh quality, and a substance called methyl furan inosinic acid (C 15H 18O9N4P) was born, which is more than 600 times fresher than monosodium glutamate, that is, the freshness should reach 60,000, which is the most delicious in the world today. It seems that with the continuous development of science and technology, human beings, as the spirit of all things, are also "delicious" in eating.