COMPOSITION, AND PROPERTIES OP KOJI. 
31 
still require correction, because, according to trials 1 and 2, 
our koji extract appears to be altered when wanned with 
lactic acid.. To eliminate this action from the results it would 
have been necessary to make parallel trials with koji extract 
and gradually increasing quantities of acid. As, however, 
only one such trial (No 2) was made, we may simply assume 
the diminution of the rotative power observed to be 0.5° in 
the presence of 0.5% of lactic acid, to have been the same in 
all other trials. On that supposition we obtain the following 
results, which approach nearer the truth than those in the 
above table : 
Trial 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 
Rotation . 5.5° 5.1° 6.8° 8.3° 8.4° 8.7° 8.7° 8.8° 8.9 9.0 
Relative effect. 100 112 62 18 15 6 6 3 0—3 
Here we see that a proportion of about 0.05% of lactic 
acid (trial 6) had the best effect, and that when the amount 
of acid is increased to 0.1% and more, the inverting power 
of koji extract is rapidly diminished, until at a content of 
0.6%, and more (trial 11-13), it is suspended. 
In an additional trial in which a mixture of cane sugar 
and koji extract containing 2% of lactic acid, had been 
heated for 2| hours to 40-45°C., we neutralized after cooling 
to a slightly acid reaction and warmed again, but the invertase 
proved not to have recovered its efficacy by the neutralization. 
In the manufacture of shoyn and miso koji is always ap¬ 
plied, along with a very large quantity of common salt; the 
former contains 150-160 grms. of sodium chloride in one litre, 
