DECEMBER, 1908. J 



533 



Edible Products, 



certain variations. The shell is of violet, 

 red, or yellow colour, sometimes even 

 nearly white, 15 to 25 centimeters long 

 and 6 to 10 centimeters thick. The shape 

 of the seed is more or less rouud, often 

 laterally compressed or flattened, when 

 it resembles the bean of Phaseolus ; its 

 length varies from 2 to 2'5 centimeters, 

 the diameter from 0'8 to 1'8 centimeters. 

 Between the fleshy and corrugate coty- 

 ledons showing convolutions on the 

 surface, lies the bitter, purple embryo 

 with its white chalaza. The cotyledons 

 of one variety are white in colour- 

 There may exist in one fruit as many 

 as fifty seeds. The loose parenchyma- 

 tuous slimy tissue (pulp) surrounding 

 the testa of the seed appears to be of 

 similar nature to the tissue forming the 

 soft inner layer of the hard fruit shell- 

 The structure of the entire fruit is 

 somewhat complicated, and nature has 

 evidently taken much pains to protect 

 the embryo by four different envelopes. 



The chief purposes of the fermenta- 

 tion process are : — 



(1) Removal or contraction of the pulp 



surrounding the seeds ; 



(2) Loosening of the connection be- 



tween the seed and its testa; 



(3) Development of colour and im- 



provement of taste. 



Some authors hold that the heat of 

 the fermentation is required to harden 

 the interior of the bean, and also pass it 

 to a second fermentation; further, that 

 another change consists in the hardening 

 or toughening of the testa of the bean, 

 whereby brittleness is avoided during 

 drying, and thus the seeds are better 

 protected against the entrance of mold 

 fungi. Various authors also ascribe to 

 the fermentation a great influence upon 

 the development of the aroma. 



As regards the first of the above- 

 named purposes, namely, the removal 

 of the slime layer attached to the seed 

 coat, a somewhat similar process occurs 

 in the fermentation of coffee. The first 

 step is the development of numerous 

 yeast cells, which find ample nutrients 

 in the sweet juice oozing from the pulp. 

 The yeasts are chiefly Saccharomyces 

 ellipscedeus and a certain amount of 

 S. apiculatus, which develop rapidly. 

 These organisms occur on fruits, as well 

 as in the dust of the air and on the 

 surface of the soil, together with 

 numerous bacteria, The alcohol formed 

 in the fermentation of the sugar by 

 these yeasts destroys the superficial 

 strata of the pulp or slime tissue, and 

 as its juice passes freely to the outside, 

 nourishment is given to innumerable 

 bacteria, among them the widely distri- 

 buted acetic bacillus. The respiration 

 of these organisms and the fermentative 



activity generate heat and gradually a 

 considerable elevation of temperature 

 is reached. 



The juice on the surface now assumes 

 a strong acid reaction, due to the 

 oxidation of alcohol to acetic acid, and 

 this suffices to destroy the remaining 

 cells of the slime layer, causing thereby 

 a considerable shrinkage of it and also 

 a further discharge of juice, as the 

 cytoplasm of the dying cells becomes 

 permeable to the interior juice. Thus 

 a considerable amount of liquid gathers 

 at the bottom of the receptacles and, 

 since this liquor has an agreeable sour 

 smell and taste, it is used in some 

 factories as vinegar. By the bacterial 

 action the attached pulp is further 

 loosened from the testa to some extent 

 and can be washed away, as is done 

 in Ceylon. In many parts of Central 

 America, however, the shrunken pulp is 

 dried with the beans, which are shipped 

 in this condition to other countries. 



The fermented and well- washed cacao 

 beans show a uniform yellowish or 

 brownish colouration of their testa. The 

 testa of unwashed fermented beans do 

 not show a uniform colouration on 

 account of the adhering films of ferment- 

 ed and shrunken pulp, which has turned 

 from the orginal colourless condition to 

 a violet brown colour, and which is 

 reduced from the original thickness of 

 O'l to 0-2 centimeter to a mere 

 film, An advantage of removing the 

 remaining films by washing consists 

 doubtless in a greater rapidity of drying, 

 whereby the danger of attack by mold 

 fungi is diminished. E. Lange holds 

 that the extra trouble is not compen- 

 sated by the additional price obtained 

 for washed cacao. Nevertheless, the 

 washing of the cacao has been recently 

 introduced in Trinidad. 



When pulped cacao is not fermented, 

 but simply dried in the sun, the slimy 

 layer around the testa shrinks consider- 

 ably, but not to such insignificant thin 

 films as after fermentation. When the 

 entire juice of the slimy layer is simply 

 dried up instead of being removed, a 

 hygroscopic condition of the product 

 results, which in moist weather becomes 

 sticky and might support fungus growth. 

 Hence, fermentation is preferable to a 

 simple drying process, and after washing 

 yields a much cleaner product. 



In the fermentation of coffee the slimy 

 layer to be removed from the testa 

 (parchment envelope) is much thinner 

 than that of the cacao seed. Hence, 

 the fermentation of coffee is of much 

 shorter duration than that of cacao. 



In regard to the second purpose above 

 mentioned, namely, loosening the con- 



