32 COCOA 



CHAP. 



(2) The formation of the essential oil. The fact 

 that fermented and dried cocoa yields a peculiar and 

 fragrant smell when boiled points to the fact that it 

 contains an essential oil. This oil can be obtained by 

 distilling the cured cocoa by means of. water vapour. 



(3) The disappearance by oxidation of a part of 

 the bitter -tasting or astringent matter. It has been 

 accepted by most authors that the cause of the bitter 

 taste of the fresh bean, which to a great extent dis- 

 appears during fermentation and drying, is caused by 

 the presence of a tannin substance. The investigations 

 of Ultee and van Dorssen, 1 however, have demonstrated 

 that this bitter-tasting substance is not a tannin, for 

 it lacks the characteristic property of the tannin sub- 

 stances to precipitate albuminoids and alkaloids. These 

 investigators accept the following formula for this 

 bitter - tasting substance, which they call cacaool : 

 C 1(5 H 16 6 . C 8 H 10 N 4 . 5H 2 0. By oxidation the cacaool 

 changes into a coloured substance, which Ultee and 

 van Dorssen presume to be identical with the cocoa- 

 red. 



Professor Harrison analysed the beans before and 

 after fermentation, but though his figures are interesting, 

 they do not contribute essentially to a better under- 

 standing of the processes of fermentation. The analysis 

 of the kernels, which are from a commercial point of 

 view much more important than the cuticles, gave the 

 following results : 



1 Ultee and van Dorssen, "Over de zoogenaamde looistof der cacao" 

 (Gultuurgids, Part ii., 1909). 



2 Hart, Cacao (1911), pp. 194-195, 206-207. 



[TABLE 



