206 



Scientific Proceedings (114). 



nevertheless the labor and expense involved are in many instances 

 prohibitive except for the production of relatively small quantities. 

 With the exception of glutamic acid no use for amino acids other 

 than for scientific purposes has been found and manufacturers 

 have as yet been unable to apply the benefits of quantity produc- 

 tion sufficiently to make these substances cheap enough for 

 extensive investigations. 



It was shown some years ago by Ikeda 1 that the taste of the 

 constituents of the seaweed Laminaria japonica is due to the 

 content of glutamic acid. This is to a certain extent also true of 

 meat extract and allied preparations. The demand for condiments 

 of this type has led to the production of the mono-sodium salt of 

 glutamic acid on a scale large enough to make it relatively cheap. 



Our experiments with Ajinomoto (a commercial preparation 

 of sodium glutamate sold by S. Suzuki & Co., Tokio, Japan) were 

 carried out with a view of using this substance as a cheap as well 

 as a convenient source for pure glutamic acid. Our results show 

 that this preparation consists largely of the mono-sodium salt 

 of glutamic acid. To isolate glutamic acid, Ajinomoto is dis- 

 solved in a small quantity of water (600 c.c. for each 100 grams) 

 and HC1 is added in an amount equivalent to the amino nitrogen 

 present. Purified charocal is then added, the mixture brought to 

 the boiling point, filtered hot and the filtrate placed in the ice 

 chest to crystallize. The crystals are drained, washed several 

 times with small quantities of ice water until free from chlorides 

 and dried. From the mother liquor and washings, after con- 

 centration, a second crop of glutamic acid may be isolated. From 

 100 grams of Ajinomoto 55 grams of glutamic acid were obtained. 

 On the basis of the amino nitrogen content (6.55 per cent.) of 

 Ajinomoto the yield corresponds to about 80 per cent, of the 

 glutamic acid present. On account of the NaCl resulting from 

 the liberation of the glutamic acid from its salt and other im- 

 purities which are present, further crystallization is not profitable. 

 The purified product yielded the theoretical nitrogen value and a 

 5 per cent, solution in 10 per cent. HC1 gave a specific rotation of 

 + 3I.5°- 



1 Ikeda, K., Communication to the 8th International Congress of Applied 

 Chemistry, 1912, xviii, 147. 



