January, 1909.] 37 



That the aroma of the cacao is chiefly 

 produced during the gentle roasting 

 process is the opinion of manufacturers 

 of chocolate from the fermented beans. 

 The fermentation seems, indeed, to have 

 nothing at all to do with the production 

 of aroma. Seeds simply dried in the 

 sun and then gently roasted may yield 

 an especially rich and aromatic chocolate, 

 as Safford* has also indicated. Hart 



No adulteration * * * is equal to the 

 flavour of the virgin cacao, provided the 

 essential oil has not been destroyed dur- 

 ing the process of roasting, during which 

 process it appears to be developed. t 



The question now arises, which com- 

 pound yields the aroma in the cautious 

 roasting of the fermented cacao beans ? 

 It is certainly not a glucosid, for neither 

 the testa nor the cotyledons of the beans 

 develop anything like a cacao flavour 

 upon being boiled for some time with 

 dilute sulphuric acid (3 to 6 per cent). 

 The same negative result was obtained 

 by boiling those materials with moder- 

 ately concentrated solution of caustic 

 potash. It seems probable that it is a 

 certain concomitant of the fat which 

 causes the production of the flavour, 

 after being moderately oxidized during 

 the drying of the beans. Only seeds 

 which the oxidizing enzyms have pro- 

 duced changes can yield the true aroma 

 by roasting, not the fresh beans. + 



In the manufacture of the cacao 

 powder of commerce the fat of the 

 cacao is removed more or less, since a 

 suitable powder cannot otherwise be 

 obtained, but in the direct manufacture 

 of chocolate this removal of the cacao fat 

 cannct be justified. It is claimed that 

 cacao fat or cacao butter is difficult 

 of digestion, but in reality cacao butter 

 is as easily digestible as cow's butter. 

 Besides, the removal of fat also diminishes 

 the aroma of the chocolate. In the 

 manufacture of chocolate in Porto Rico, 

 fermented cacao seeds are placed in a 

 small baker's oven for about one hour, 

 until the testa have become very brittle 



* Compare the quotation in the introductory 

 remarks to this article. 



f These words contradict his other opinion, 

 however, quoted above in regard to the in- 

 fluence of fermentation on aroma. 



+ Fresh beans were crushed, washed with 

 alcohol, and extracted with either. Neither the 

 extracted fat nor the seed powder developed on 

 moderate heating any flavour resembling that 

 of cacao ; only the alcohol extract yielded thus 

 a very faint flavour of cacao. On evaporation of 

 the alcoholic extract another aromatic odour is 

 noticed. 



Edible Products. 



and can be easily removed. This roast- 

 ing temperature is kept considerably 

 lower than that required for baking 

 bread. The cacao butter is not removed 

 in Porto Rico, and therefore the chocolate 

 manufactured there has an exquisitely 

 fine aroma. 



Summary. 



The fermentation process itself is due 

 in the first place to yeast cells which 

 multiply rapidly in the saccharine juice 

 oozing from the pulped cacao and produce 

 alcohol and carbon dioxid. In the second 

 place bacteria participate, which develop 

 rapidly after a certain time, and change 

 the alcohol formed by the yeast by 

 oxidation, either wholly or partly, into 

 acetic acid. These processes cause a 

 rise of temperature and the death of 

 the cells of the seed and slime tissue, 

 whereupon the juice of the slime tissue, 

 more or less altered, collects at the 

 bottom of the receptacles, together with 

 the acetic acid produced. 



The chief object of the fermentation is 

 to shrink the slime tissue or pulp at- 

 tached to the testa of the seed, allowing 

 the remnants either to be washed away , 

 as is doue in Ceylon, or dried upon 

 the seed forming an irregular brown 

 film upon the testa. The advantage of 

 thus changing the voluminous slime 

 tissue lies in the increased facility of 

 quickly drying the seed. In this regard 

 there exists a close analogy to the 

 fermentation of coffee. The loosening 

 of the adhesion between seed and its 

 envelope and the hardening of thia 

 envelope (testa) are claimed as further 

 effects of fermentation. 



The fermentation has also an indirect 

 influence on changes going on within the 

 seed, inasmuch as by the temperature 

 produced (40° to 50° C )the cells of the 

 seed are killed, thus liberating the oxi- 

 dizing enzyms, which cause the forma- 

 tion of the brown colour, by oxidation 

 of the tannin of the seed. This brown 

 colouration is increased during the 

 drying process and finally by the 

 roasting. 



The taste of the raw cacao bean is 

 not only altered by the partial oxidation 

 of tannin during the fermentation or 

 sundrying of the seed, but also by 

 products of roasting. 



The action of oxidising enzyms, as 

 well as the final roasting process, play 

 a part in the development of the aroma. 

 — Porto Rico Agricultural Experiment 

 Station. For 1907. Issued May 4th, 

 1908. 



