Monosodium glutamate (MSG): Production History


In 1907, professor of the Imperial University of Tokyo Kikunae Ikeda began to scientific research, the purpose of which was to identify the component “minds” in the algae. During the year, the professor was able to isolate, purify and identify the main components of the minds, and he quickly received a patent for it.

Glutamate natriyaV 1909 Suzuki Seburosuki businessman with Ikeda began commercial production of monosodium l-glutamate (in the EU is referred to as MSG, according to international classification – the food additive E621). The first industrial production process is the method of extracting MSG, wherein the vegetable protein is mixed with hydrochloric acid to break peptide bonds. From this starting material emits hydrochloride L-glutamic acid, which is then purified to a level of MSG, it is known to all white crystals of sodium glutamate.

Initially MSG production was limited due to technical disadvantages of the described method and its time consuming and a large amount of by-products; more productive ways appeared only 1950. One of them was a direct chemical synthesis, which was used from 1962 until 1973. With this method the starting material is acrylonitrile, in the course of which certain chemical processes crystallized dl-glutamic acid. However, the most common was invented in 1956 by the method of direct fermentation. Advantages of the method of fermentation (reduction of production costs plus a smaller environmental costs) were so strong that make all the polls glutamate manufacturers to switch to fermentation was not difficult. Today, the total volume of production by fermentation MSG estimated 2 million tons per year (2 billion pounds per year). At the same time, a future increase in the production of monosodium glutamate, may require to search for new technologies.

Opening of glutamate and start production

In 1907, Professor Ikeda Kikunae started research projects with the aim to identify located in algae (Laminariaceae) substance, gives the dish a unique “bouillon” (or “meat”) taste, widely present in the Japanese dishes catering establishments, where a long tradition is eating soup with algae. His study was based on the hypothesis that algae contain one or more substances which form a taste that can not be classified as bitter, sour, salty or sweet (known basic tastes while). He called the alleged fifth basic taste “umami.” More broadly, Ikeda hoped that if successful the research could find commercial applications in the form of spices, which could contribute to the improvement of Japanese dishes. In 1908, he identified the taste of umami in one of the components of algae – l-glutamate. Then Ikeda Kikunae filed a patent production of new seasonings consisting primarily of salt l-glutamic acids. After a while Seburosuki Suzuki, known entrepreneur on the chemical and pharmaceutical industry, in cooperation with Ikeda engaged in the production and sale of seasonings invented. In 1909 she was named “Ajinomoto” (“essence of taste”) and was registered as a trademark.

Method of extraction: very first industrial production method

Production of glutamate natriyaStanovlenie industrial production of glutamate began in December 1908. It was the first attempt to produce amino acids in industrial volumes, so the lack of any experience made the process very time consuming. The process itself consists of 3 parts: the extraction, separation, purification.

step extract

Professor Ikeda proposed to use as a raw material of wheat gluten, because it has the highest content of l-glutamine industrially available raw materials. After hydrolysis, the protein was converted to l-glutamine in l-glutamic acid; It should be noted that the total content of glutamate (the glutamate + glutamine) the hydrolysis of wheat gluten is more than 30 g per 100 g protein. Gluten is first separated from the flour by washing out the starch from the dough. The resulting crude gluten was placed in a clay container (called the original term “pots for games dom¸dzi”), was mixed with hydrochloric acid and subjected to intense heat treated for 20 hours. By the way, in the course of the experiments were used a great variety of capacities, but it is old-fashioned “pots dom¸dzi” were the most resistant to hydrochloric acid in combination with a high temperature. The resulting protein hydrolyzate was then subjected to filtration to remove black precipitate, later called humus, which was obtained by the reaction of amino acids and carbohydrates. Then he again placed in a clay pot for 24 hours to concentrations. More further concentrate was poured into a clay pot, but for a month to allow the hydrochloride salt of l-glutamic acid up into a crystal.

Crystallization hydrochloride-l-glutamic acid was very effective for retrieval l-glutamate hydrolyzate since it is the only amino acid salt in the hydrolyzate with very low solubility with respect to concentrated hydrochloric acid. Besides, the resulting crystal has a very high resistance to dissolution by other amino acids: the molecules l-glutamic acid crystal form along the axis of binding – aminoplasts NH-Cl and -karboksionnymi tsepochkomi hydrogen bonds OH-Cl. Structurally speaking, it is difficult to incorporate the other amino acids in a growth of the crystals, which makes the process of crystallization handle (partial) purification. Unusual crystal structure also limits the extent to which other formulations gluten hydrolyzate (coloring agents, other organic acids) are united in growing crystals or otherwise antagonize the crystallization process. This simple process of crystallization l-glutamate could thus be recovered from the hydrolyzate with a high percentage output and with improved purity. However, it should be noted that this process was very dangerous: you can imagine what effect the sulfuric acid vapor at work, metal construction and the local atmosphere.

Stage selection

The crystals of hydrochloride, l-glutamic acid were separated from the liquid by means of filters and re-dissolved in water. This solution was again filtered to remove the mulch. PH-component (hydrogen index) is then adjusted to the isoelectric point-l-glutamic acid (pH 3.2) with sodium or potassium hydroxide, and this solution was left for one week to afford l-glutamic acid-crystallize. This step increased the purity of the crystals is extremely following reason. In crystals of l-glutamic acid, there are two polymorph: metastable, granulated -form and stable, thin, plate--form. -form increases faster -form solutions containing the other amino acids. And, in certain growing chain hydrogen compounds, -dominant forms specifically takes molecule-l-glutamic acid from l--amino acids and -carboxyl residues. Since the aqueous solution of the hydrochloride salt l-glutamic acid-established in the early stages of production (described above) is still comprise other amino acids, -form glutamic acid was the dominant crystal formed in said pH-indicator 3.2. Thus, improving the purity of the substance was obtained due to the fact that the grown crystals with -form did not contain other amino acids.

Purification step

The crystals were isolated l-glutamic acid was re-dissolved in water and placed in an enamel-lined vessel. There was added sodium bicarbonate to bring the pH-indicator to the neutral level (using a litmus paper). Monosodium glutamate solution was discolored by adding activated charcoal and filtering. The filtered solution was concentrated by heating and cooled in enameling vessel, causing rapid formation of crystals of monosodium l-glutamate. Clumps of crystals of monosodium glutamate pulverized and separated from residual solution in the centrifuge. The resulting powder was dried, sieved and packed as a final product already.

In March 1909 was successfully carried out the first batch of monosodium glutamate (MSG), held for sale. This powder was light brown with a purity of approximately 85% (compared with the growth in an absolutely pure solution glutamate is a rhomboid crystals transparent but because of the presence of -form crystal growth is highly dependent on the presence of other amino acids). When other amino acids (e.g., l-alanine), glutamate crystals grew in small, sometimes almost as a powder. But in the coming years, thanks to the development of treatment technology, was able to produce glutamate in the form of transparent crystals.