Chemical Encyclopedia – Monosodium Glutamate

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Monosodium glutamate is a type of seasoning; its main component is monosodium glutamate (abbreviated as MSG), which is the monosodium salt of L-glutamic acid. Chemical formula: C5H8O4NNa·H2O. Appearance: white crystalline powder. Melting point: 225°C. It is highly soluble in water. Its main function is to enhance the umami flavor of foods; it was discovered by the Japanese company Ajinomoto in 1909 and patented. Industrial preparation methods: fermentation, protein hydrolysis, and synthetic synthesis. Fermentation is a commonly used method in industrial production today, as it offers high yields, requires relatively less food, has relatively simple equipment, and results in lower costs. The raw materials used include carbon sources derived from starches, as well as nitrogen sources such as urea and ammonia. Through fermentation by glutamate-producing strains such as Micrococcus glutamicus and Brevibacterium, intermediate products containing glutamate are obtained. The intermediate product is neutralized using water-soluble basic compounds containing sodium ions such as sodium carbonate and sodium hydroxide, and finally purified to obtain sodium glutamate crystals. Protein hydrolysis is also a common preparation method, but it is used less frequently than fermentation due to the large amount of grain required for its production. The principle involves hydrolyzing proteins that contain glutamate, purifying the glutamate from them, redissolving it in water and neutralizing it; after neutralization, sodium glutamate is purified to yield crystals. Since there are many types of amino acids that make up proteins, glutamate obtained directly through hydrolysis is just a small portion of the amino acids resulting from hydrolysis. Its efficiency is relatively low because the remaining amino acids cannot be utilized (including the carbon, hydrogen, nitrogen, and other elements they contain). Although the synthetic method does not require grain but rather specific non-grain organic compounds, it is not widely used due to its complex preparation process, the need for expensive high-temperature and high-pressure equipment, and thus high costs. Utility: Sodium glutamate, the main component of monosodium glutamate, has therapeutic effects on chronic hepatitis, hepatic coma, neurasthenia, epilepsy, acid deficiency in the stomach, and other conditions. Excessive intake may lead to stomach cancer and other human internal organ diseases.