148 The Fermentation of Cacao 
As a further check the residue, at another 
test, was heated for five minutes to 100° C. 
before adding. the violet mass; here after 
standing for days there was not the slightest 
trace of change of colour. 
From these tests it follows that the dis- 
colouration of the beans, which die at a tem- 
perature of about 45° C. during the fermentation, 
is caused by a substance contained in the seed 
itself, and which must be an enzyme, seeing 
that it can be destroyed by boiling heat, is 
precipitated by alcohol, and causes the dis- 
coloration by the medium of a minute quantity. 
The temperature at which the enzyme is 
destroyed appears to be somewhere about 
FO Ta. 
For the purpose of ascertaining the activity 
of the enzyme-containing residue, a few further 
tests were made, In these it was noticed that 
cane-sugar did not split, an invertase thus 
appeared to be lacking. Amygdalin, however, 
did so. 
This observation gave us an idea as to the 
nature of the reaction which causes the beans 
to turn brown. 
In the beans, the above-mentioned glucoside’ 
does not exist, but another, z.e., cacaonine, is 
1 By glucosides are understood those substances 
which by the action of acids, alkalis or enzymes become 
divided, so that in addition to more or less compound 
bodies a kind of sugar, usually dextrose, forms. Glu- 
cosides appear almost exclusively as plant substances. 
