COCOA 439 



a stout radicle, situated at the hilum portion of the seed; odor 

 chocolate-like, and taste slightly bitter. 



In the roasting of the seeds, the seed-coat is more readily detach- 

 able and the embryo more easily broken into smaller fragments. 

 By a process of winnowing the seed-coat is separated and constitutes 

 what is known in commerce as Cocoa Shells. The broken embryo 

 constitutes the product known as cocoa nibs or cracked cocoa. 



PLAIN CHOCOLATE or cocoa mass is obtained by grinding the 

 broken cotyledons (cocoa nibs) in a mill and separating the pasty 

 mass, which is molded into forms that usually weigh a pound. COCOA 

 is the plain chocolate from which a part of the fat (cocoa butter) has 

 been removed, the resulting product being then powdered. SWEET 

 CHOCOLATE is plain chocolate to which sugar and various flavoring 

 substances are added. MILK CHOCOLATE is a sweet chocolate to 

 which " milk powder " is added. 



Powder. CACAO PREPARATA or COCOA. (Fig. 192). Reddish- 

 brown; consisting chiefly of protein grains, oil and starch grains, the 

 latter from 0.003 to 0.008 mm. in diameter; fragments with brownish 

 or purplish-brown contents (cacao red) ; crystals of Cacao butter in 

 small prisms or needles; few fragments of seed-coat consisting of 

 hexagonal epidermal cells, and -a peculiar mucilage layer of small 

 tabular cells and a layer of nearly iso-diametric stone cells about 0.010 

 mm. in diameter, having walls which are about 0.004 mm. in thickness. 



Cacao starch grains show a tendency to cohere and on gently 

 heating a section in water, after removal of part of the oil with ether 

 or chloroform, the compound grains swell into angular, rounded or 

 irregular masses which vary from 15 to several hundred microns in 

 diameter (Fig. 192, B). The smaller masses thus produced bear a 

 close resemblance to the starch grains of corn and wheat. The 

 central triangular marking of the mass, which resembles that of a 

 corn starch grain, is formed from the adjoining walls of three indi- 

 vidual grains. Most of the aggregates, however, swell into rounded 

 masses (0.035 mm. in diameter) resembling wheat starch grains, and 

 have a clearly defined wall with nearly homogeneous, hyaline con- 

 tents. They may be distinguished from wheat starch by the use of 

 dilute alkali or acid solutions, which cause an immediate breaking 

 down of the masses without the successive changes in structure 

 noticed on similar treatment of wheat starch grains. 



Constituents. The seeds contain 35 to 50 per cent of; a fixed oil 

 known as cacao butter and official as Oleum Theobromatis ; 15 per 

 cent of starch ; 15 per cent of proteins ; 1 to 4 per cent of theobromine ; 

 0.07 to 0.36 per cent of caffeine, about 0.5 per cent of sugar, and also 



