60 COCOA AND CHOCOLATE 



coming tinged with brown. The action resembles the brown- 

 ing of a freshly-cut apple, and has been shown to be due to 

 oxygen (activated by an oxidase, a ferment encouraging com- 

 bination with oxygen) acting on the astringent colourless 

 substance, which, like the photographic developer, pyrogallic 

 acid, becomes brown on oxidation. 



(3) Aroma. A notable change is that substances are created within 

 the bean, which on roasting produce the fine aromatic odour 

 characteristic of cocoa and chocolate, and which Messrs. 

 Bainbridge and Davies have shown is due to a trace (o.ooi 

 per cent.) of an essential oil over half of which consists of 

 linalool.* 



(4) Stimulating Effect. It is commonly stated that during ferment- 

 tation there is generated theobromine, the alkaloid which 

 gives cacao its stimulating properties, but the estimation of 

 theobromine in fermented and unfermented beans does not 

 support this. 



(5) Consistency. Fermented beans become crisp on drying. This 

 development may be due to the " tannins " encountering, in 

 their dispersion through the bean, proteins, which are thus 

 converted into bodies which are brittle solids on drying (com- 

 pare tanning of hides). The " hide " of the bean may be 

 similarly " tanned " the shell certainly becomes leathery 

 (unless washed) but a far more probable explanation, in 

 both cases, is that the gummy bodies in bean and shell set 

 hard on drying. 



We see, then, that although fermentation was prob- 

 ably originally followed as the best method of getting 

 rid of the pulp, it has other effects which are entirely 

 good. It enables the planter to produce a drier bean, 

 and one which has, when roasted, a finer flavour, colour, 

 and aroma, than the unfermented. Fermentation is 

 generally considered to produce so many desirable 

 results that M. Perrot's suggestion*)* of removing the 

 pulp by treatment with alkali, and thus avoiding fer- 

 mentation, has not been enthusiastically received. 



Beans which have been dried direct and those which 

 have been fermented may be distinguished as follows : 



* Journal of the Chemical Society, 1912. 

 j- Comptes Rendus, 1913. 



