GB347258A - An improved process for the manufacture of mono-sodium glutamate and like glutamic acid salts - Google Patents

Abstract

In the production of salts of glutamic acid such as monosodium glutamate by hydrolysing gluten flour with hydrochloric acid, neutralizing the hydrolysate, and treating the glutamic acid formed with a suitable base, decomposition of the amino-acids and loss of hydrochloric acid while concentrating the hydrolysate by evaporation is prevented by carrying out the evaporation in vacuo at a low temperature. According to an example, gluten flour is mixed with concentrated hydrochloric acid and allowed to stand until the mass becomes liquid. The mixture is boiled for six hours under reflux, then filtered hot, and evaporated to half its volume in vacuo at 45 DEG C. The concentrate is mixed with an equal volume of concentrated hydrochloric acid and allowed to stand until glutamic acid crystallizes out. The crystals are filtered, washed with hydrochloric acid, dissolved in boiling water, and the solution is treated with decolourizing charcoal. The decolourized solution is filtered, and the exact quantity of caustic soda required to neutralize all the free and combined hydrochloric acid is then added. The liquor is cooled and the precipitate of glutamic acid is removed therefrom and dried. A weighed quantity of the precipitate is suspended in water, the exact quantity of caustic soda required to form monosodium glutamate is added thereto, and the solution is evaporated in open pans until the salt sets to a crystalline mass which is then broken up and powdered. By using the hydroxides or carbonates of such metals as potassium, calcium, or magnesium instead of caustic soda, the glutamic acid salts of these metals can be obtained.