COMPOSITION, AND PROPERTIES OF ROJI. 
19 
I. Cane sugar. The mixture applied consisted of 150 o.c. 
of a cane sugar solution of about 10% and 100 c.c. of koji 
extract. The optical rotations found, were : 
Solution of cane sugar . 13.7° 
Extract of koji, fresh. 11.7° 
,, „ „ , after heating . 11.5° 
Mixture, after heating . 5.5° 
If while heating the mixture of sugar solution and koji 
extract no inverson of the former had taken place, the 
rotation would have been 12.8°, while it actually had diminish¬ 
ed to 5.5.° These figures enable us to calculate the proportion 
of cane sugar that had undergone inversion, in the following 
way: 
The original cane sugar solution diluted with koji extract 
had a rotative power of 12.8° ( = 6.18 gnus, of cane sugar in 
100 c.c.), of which 8.2° were due to the sugar, while of the 
5.5° observed after heating only 0.9° were caused by the cane 
sugar and its inverted products, the remaining 4.6° being due 
to the koji extract. 
If the whole sugar had been inverted, the rotatory power of 
its products would have been—2.6.° Applying II. Landolt’s 5 
formula for the calculation of the cane sugar not inverted : 
r = f (A-B) 
in which r = the proportion (grms.) of cane sugar still present 
in 100 c.c., A = the rotation of the partly inverted sugar 
( + 0.9°), B = the rotation after complete inversion( —2.6°), wc 
obtain : 
r = A (0.9— —2.6) = i- 3.5 = 2.0 grms. 
Of the 6.18 grms. of cane sugar 2.0 grms. had accordingly 
not been inverted. Hence 6.18 — 2.0 = 4.18 grms. e.g. nearly 
70% of the whole sugar had undergone inversion under the 
influence of the soluble ferment of koji. 
6 Berichte der Königl. l’reuss. Akademie der Wissenschaften zu Berlin 
1887, 2. Halbbd., p. 980. 
