200 



NISHIMURA : THE CHEMISTRY OF 



The production of the small amount of lactic acid and acetic acid 

 by bacteria seems not essential, as it only takes place at the sur- 

 face of tho wort in summer time. The great amount of salt added 

 is intended principally to prevent bacterial growth and the fer- 

 mentations caused by it ; but at the same time the action of 

 enzymes is very much retarded by the high percentage of sodium 

 chloride. 



Thus O. Kcllncr, Mori and Nagaoka}'' proved that by adding 

 of sodium chloride to the mixture of koji extract and starch, 

 the amount of sugar formed at 40°C. after 2 hours was only \ of 

 that in the control solution without sodium chloride. In another 

 experiment they found that with 12^ of sodium chloride only 

 4.0^ and that with 20^ of sodium chloride only of sugar, 



in comparison with that formed under normal circumstances. 



In another experiment, an addition of 20,% of sodium chloride 

 decreased the amount of the sugar produced to 7.7% of the nor- 

 mal quantity. 



If we heat the soja sauce wort to 8o-loo°C. no action what- 

 ever is noticed. Of course, the enzymes are killed by this operation. 



As the present method of manufacture of soja sauce requires 

 much time and therefore a considerable amount of unremunerative 

 capital, it seemed to me of great importance to find some way by 

 which the processes could be shortened. Two points seemed to 

 me worthy of consideration. 



1. To hasten the action of enzymes. 



2. To produce the agreeable taste and flavour in the same 

 measure as the enzyme action is hastened. 



These processes seemed to me independent of each other. 



In order to hasten the action of the enzymes of the soja koji, 

 I crushed freshly jDrepared wort so as to increase the surface to 

 be acted upon. 



In the factory neither the soja beans nor the wheat are finely 

 pulverized, hence the changes must be much retarded, as the en- 

 zymes penetrate but very slowly into the grains. 



And farther I diluted the mixture with an equal amount of 

 water, thereby diminishing the percentage of salt, and hence 

 accelerating the action of enzymes ; of course by this means the 

 conditions for the development of certain bacteria were rendered 



(I) Bull. College of Agriculture ; Vol. I, No. 5. 1889. 



