On the Diastase of Koji. 



299 



" On the Diastase of Koji. 99 * By R. W. Atkinson, B.Sc. (Lond.), 

 Professor of Analytical and Applied Chemistry in the Uni- 

 versity of Tokdo, Japan. Communicated by Professor A. 

 W. Williamson, For. Sec. R.S. Received March 3. Read 

 March 10, 1881. 



SUMMAEY. 



Section I. — Preparation of the Koji. 



Mechanical preparation of the rice. Addition of spores of Eurotium 

 oryzece (Ahlb.). Growth of mycelium in warm chamber. Rise of 

 tamperature during growth sufficient to preserve the temperature of 

 the chamber constant, and, in winter, much above the temperature 

 :jf the outer air. Temperature of koji itself from 10° to 23° F. above 

 that of the chamber. 



Activity of growth shown by the rapid replacement of oxygen in a 

 confined portion of air by carbonic acid. 



Loss of weight of the rice during the growth of the fungus. 



Section II. — Action of Water on Koji. 



Amount of solid matter dissolved depended upon time and tempera- 

 ture of digestion, and upon the proportion of water used. 



Amount of albuminoids dissolved depended mainly upon the duration 

 of digestion. 



Temperature of greatest change in cold water extract of koji. 



Section III. — Action of Koji Extract upon some Carbohydrates. 



Extract of koji causes inversion of cane-sugar. It also effects the 

 hydration to dextrose of maltose and dextrin. Curve A. 



Extract of koji breaks up the starch molecule into maltose and 

 dextrin ; the maltose is quickly hydrated, and the products after some 

 cime are dextrin and dextrose. 



Experiments showing the action of koji extract upon starch-paste 

 at various temperatures from 4 — 10° C. to 70° C. Curves B to H. 



Effect of common salt in neutralising the hydrating power of koji 

 extract. 



* I feel that some apology is needed for using the Japanese word koji, but as 

 there is no foreign product in any way resembling it, I have thought that there 

 would be less danger of confusion arising by retaining the Japanese word than by 

 using the word " malt." As will be seen from the following description, the nature 

 of this substance is quite different from that of malt, so that the use of that word 

 might lead to erroneous impressions. 



The 6 is pronounced long, as it is a contraction for the diphthong au, the word 

 being written in Japanese kauji, but pronounced as written above. 



