250 BIOLOGICAL ACTIVITIES OF MOLDS 



mycelium develops, this process taking about 3 days. The molding 

 mass is then placed in a concentrated salt brine where the aging 

 takes place. The liquor may be agitated occasionally to advantage. 

 During this aging process, an enzymatic digestion occurs; the cell 

 structure of the bean is broken down, the small amount of starch is 

 converted to sugar by the diastase and the proteins of the bean are 

 hydrolyzed by the proteolytic enzymes of the mold. The fermenting 

 liquor acquires a dark brown color during the aging process which 

 may extend over a period of a few months to a few years. The salt 

 concentration is very high (about 15 per cent), and though various 

 yeasts and bacteria are present they play only a minor role in the 

 process. The final product, after pressing, boiling, and filtration, 

 bears a striking resemblance to meat extract, in both flavor and com- 

 position. The resemblance in flavor to meat extract is due to the 

 presence of the sodium salt of glutamic acid, an amino acid formed 

 from the hydrolysis of soybean proteins during the aging. Soy sauce 

 reaches occidental tables in condiments such as Worcestershire sauce 

 of which it forms the base. 



Miso (soybean paste or porridge) is prepared by mixing mashed, 

 steamed soybeans, salt, and koji and allowing the whole to undergo 

 a brief fermentation. The bean is partially digested, the starch and 

 proteins are hydrolyzed to produce the characteristic flavor, and 

 the high salt concentration prevents the development of putrefactive 

 organisms. Miso may be used for broths or it may be used for 

 "curing" vegetables, fish, and other foods. 



Tamari is a soybean sauce differing from shoyu in that rice is 

 often added and the dominant organism involved in bringing about 

 the changes is A. tamarii. The ripening process is generally shorter. 



Mucor Rouxii has been used industrially for the production of 

 alcohol. It secretes both amylase and the zymase complex of en- 

 zymes, and can therefore produce alcohol directly from starch with- 

 out any malting process. It is used in the Orient for preparing alco- 

 holic beverages from rice. It is marketed under the name Chinese 

 yeast, in little balls of rice meal, much as we in the Occident sell 

 yeast cakes. It has also been used commercially for alcohol produc- 

 tion in Europe. 



A number of species of Rhizopus closely resembling Rhizopus 

 nigricans have been obtained from ferments used in oriental coun- 

 tries. They are all very active in changing starch to sugar. R. 

 japonicus occurs as a contaminant or accompanying ferment, along 

 with strains of the A. jiavus-Oryzae group, in koji. It is actively 

 diastatic; and hag been used commercially in Europe in malting 



