238 The Fermentation of Cacao 



These bodies tend to disappear if the beans 

 are kept for a length of time. Perhaps a few 

 others are formed, in which case the beans (all 

 else being equal) would improve with keeping. 



Summary of the Changes which take place. 



(1) The testa is rendered more brittle and 

 acts as a diffusion membrane. Cacao red and 

 other constituents diffuse into it. 



(2) The kernels assume a diffuse chocolate 

 colour, are plumped up and become less ad- 

 'herent to the testa ; this is the action of the 

 volatile substances and the carbonic acid gas. 



(3) The sugar and, to some extent, the starch 

 are converted to lower products, such as alcohol, 

 acetic acid and carbonic acid gas. 



(4) The fats are lost to a very slight extent. 



(5) Theobromine and cacao red are also very 

 slightly lost. 



(6) Some of the bitter principle is reduced or 

 diffuses out of the bean. 



(7) Acetic acid and alcohol become present 

 in the kernel. 



The Isolation and Cultivation of the Organisms 

 which Ferment Cacao. 



The principle of the cultivation of organisms 

 is to provide them with a medium which con- 

 tains only food material and substances which 

 are favourable to them. 



The medium must vary with different classes 

 of organisms : thus yeasts will flourish upon 

 saccharine media in which there is an absence 



