124 The Philippine Journal of Science 



191S 



That the fermentation is the result of biological action is the 

 conclusion of J. Sack.' 



Preyer" has isolated a yeast, Saccharomijces thtohromx, from 

 fermenting cacao and has recommended the use of the pure cul- 

 ture of this for the initiation of the fermentation. Besides the 

 above he observed ^S. cevevisiie, S. ellipsoidies, and S. membranae- 

 faciens in fermenting cacao. Others have noted the presence of 

 Penicillimn and 5. apictdatiia. 



However, not much success has been attained with the use of 

 pure cultures of yeasts, and not much development can be looked 

 for along this line, since the use of a pure strain of yeast would 

 necessitate the sterilization of the culture medium, the cacao. 

 Sterilization would destroy the enzymes present. Behrens " has 

 pointed out that the changes desired from fermentation do not 

 occur when the enzymes are destroyed. 



That the color change in the bean from white or violet to 

 brown is only indirectly produced by fermentation is maintained 

 by Loew." He insists that the brown coloration is due to the ac- 

 tion of the oxidases or oxidizing enzymes, since this same brown 

 coloration is produced when the beans are crushed and exposed 

 to the air. These oxidases are stored up in the protoplasm of 

 the bean of the cell and are liberated when the cells are killed, 

 without injury to the enzyme. The enzyme then becomes active. 



It is a very generally accepted belief that enzymes are an im- 

 portant factor in the changes tobacco undergoes during the curing 

 process. With this in mind Oosthuizen and Shedd '■' have inves- 

 tigated the enzymes of the tobacco plant. 



Many plants and plant products '" are being investigated to 

 discover the enzymes present and thus throw some light on the 

 changes they undergo when ripening and germinating and their 

 influence on the system when used for foods. 



On account of the great interest manifested in enzymology and 

 in the hope that some light may be thrown on the cause of the 

 changes taking place in the fermentation of cacao and on the 

 real nature of the changes themselves, this investigation has been 

 undertaken. 



' H. H. Smith, The Fermentation of Cacao. John Bale Sons and 

 Danielsson, London (1913), 138-141. 



' Tropenpflanzer (1901), 5, 151. 



' Lafar, Handbuch der technischen Mykologie, 1 , 655. 



^ Porto Rico Exp. Sta. Rep. (1907). 



'Journ. Am. Chem. Soc. (1913), 35, 1289. 



'" Chelpin, General Chemistry of the Enzymes. Trans by Pope. John 

 Wiley & Sons (1912). 



