COCOA 253 



The chief purposes of the fermentation process are ^ : — 



1. To arrest the germinating power of the seed; 



2. To remove or contract the pulp siirrounding the seed ; 



3. To loosen the connection between the seed and its testa ; 



4. To develop the colour of the bean and to improve the 

 taste of the cocoa. 



The separation of the pulp is originally due to the activity 

 of yeasts, which develop in the sweet juice oozing from the 

 pulp ; an alcoholic fermentation takes place in the inner 

 portions of the mass, which gives place to an acetic fermenta- 

 tion in those portions in contact with air. These changes 

 result in an elevation of temperature and a considerable 

 discharge of acid juice, which is sometimes used as vinegar. 

 At the same time the beans become loosened from their 

 surrounding integument, from which they can afterwards be 

 easily separated by washing. 



The bean in its fresh state has a violet colour ; on exposure 

 to air the violet colour changes to a deep brown. The change 

 of colour from purple to brown takes place to some extent 

 during the fermentation process, and is completed in the 

 subsequent drying. It has been shown that this change of 

 colour is due to the action of an oxidase in the cocoa bean. 

 If the bean is boiled or treated with acid, no change of colour 

 can afterwards be produced, showing, therefore, that it is due 

 to the action of an enzyme. It appears that both an oxidase 

 and a peroxidase are present. Thus, if a freshly cut bean is 

 moistened with tincture of guiachum, a blue colour is rapidly 

 produced, indicating the presence of an oxidase. If the bean 

 is crushed with a little water and heated for five minutes to 

 75° C, no coloration is given with guiachum, showing that the 

 oxidase is destroyed at this temperature. On addition of 



' See The Fermentation of Cacao and of Coffee, by Dr. Oscar Loew, pub- 

 lished in the Annual Report of the Porto Rico Agricultural Experiment 

 Station for 1907, to which the author acknowledges his indebtedness in 

 the present and the succeeding sections. 



