1881.] Prof. R. W. Atkinson. On the Diastase of Koji. 523 



III. "On the^ Diastase of Koji." By R. W. Atkinson, B.Sc. 

 (Lond.), Professor of Analytical and Applied Chemistry in 

 the University of Tokio, Japan. Communicated by Pro- 

 fessor A. W. Williamson, For. Sec. R.S. Received March 

 3, 1881. 



(Abstract.) 



The paper contains the results of an investigation into the nature 

 of the material used in Japan for converting starch into sugar in the 

 brewing operations. This substance " koji " is prepared from steamed 

 rice by allowing the spores of a fungus, mixed with the grain, to 

 vegetate over the surface. Details of the manufacture are given, and 

 it is shown that the rice suffers a loss of 11 per cent., calculated 

 upon the substance dried at 100° C. At the same time a great evolu- 

 tion of heat occurs. 



A solution of the soluble portion of the " koji " thus prepared is 

 shown to possess properties analogous to those of malt-extract, although 

 differing from it in some important respects. It rapidly inverts cane- 

 sugar and hydrates maltose and dextrin. It liquefies starch-paste, 

 forming at first maltose and dextrin, but giving as ultimate products 

 dextrose and dextrin. Curves accompany the paper showing the 

 action of the extract of "koji" upon starch-paste at different tem- 

 peratures. 



The paper concludes with an examination of the change which the 

 rice grain undergoes by the growth of the mycelium of the fungus, 

 and it is pointed out that the principal effect produced by the growing 

 plant is to render the insoluble albuminoids previously existing in the 

 rice soluble. 



