THE CHEMISTRY OF COCOA 37 



Opinions differ greatly as to the way in which 

 theobromine occurs in the fresh seed, and this point is 

 not yet wholly elucidated. It may be that it occurs 

 combined with glucose in the form of a glucosid (though 

 this is not probable), or that it is combined with the 

 bitter substance cacaool, as Ultee found was the case 

 with the closely related caffeine. At any rate, in the 

 fresh seed it is not present in a free condition, but is 

 set free during fermentation and drying. 



The chemical formula is CgNJiLOg (CH 3 ) 2 . 



Theobromine is responsible for the stimulating effect 

 of cocoa, as the caffeine is in coffee and the thein in tea. 



It occurs not only in the kernels of the seeds but 

 in the cuticles, though only to a small amount, and 

 final] y also in the leaves. The quantity found by 

 Dekker in the young leaves of Java cocoa amounted 

 to no less than 0*5 per cent, in the older leaves to 0*3 

 per cent, while full-grown leaves were almost free 

 from the alkaloid. 



Caffeine, a substance closely related to theobromine 

 (formula : C 5 N 4 H0 2 (CH 3 ) 3 ), is of much less importance 

 in the cocoa plant. According to Zipperer, the quantity 

 present in marketable cocoa is about 0'05 to 0'36 per 

 cent ; in Guiana cocoa (fermented and cured) Harrison 

 found in the kernels 0'06 to 0'41 per cent, in the 

 cuticles 0'24 to 0*54 per cent. The methods used and 

 the figures obtained need, however, to be revised. 



Cacaool and cacaonine in the fresh seeds and cocoa- 

 red in the fermented and cured seed (better : in the 

 dead seed) have already been mentioned. 



It may be added, finally, that Trojanowski put 

 forward a method of distinguishing the different kinds 

 of marketable cocoa by means of chemical reactions. 

 His determining table, which is to be found in various 

 handbooks, 1 is, however, quite unreliable. 



1 Jumelle, Le Cacaoyer, p. 57, etc. 



