NITROGENOUS CONSTITUENTS OF COCOA. 939 
For percentages of theobromine in cocoa and cocoa preparations, see 
tables of analyses given below; for methods of quantitative determina- 
tion, see methods of analysis given below. 
The commercial importance of theobromine at present offers no temp. 
tation to remove it from cocoa preparations before placing them on the 
market. 
Small percentages of caffeine have been found in cocoa beans, espe- 
cially in the shells. Itis separated from the theobromine by solution in 
eold benzol, in which the theobromine is practically insoluble. Weig- 
mann! reports 0.17 per cent in cocoa mass and 0.113 to 0.190 per cent in 
cocoa Shells; Bell,’ traces to 0.25 per cent in the bean and 0.33 per cent 
in the shells. 
Nonalkaloidal nitrogenous substances.—Stutzer? classifies the nitroge- 
nous constituents of cocoa, as follows: 
(1) Nonproteids, substances soluble in neutral water solution in presence of 
Cu(OH), (theobromine, ammonia, and amido compounds). 
(2) Digestible albu-nen, insoluble in neutral water solution in presence of 
Cu(OH)., but soluble when treated successively with acid gastric juice and alkaline 
pancreas extract. 
(3) Insoluble and indigestible nitrogenous substances. 
In the same article he writes as follows in regard to the food value of 
the nitrogenous constituents of cocoa: 
The group of nitrogenous constituents is of great importance in all foods, espe- 
cially their content of digestible albumen. Among the general public the opinion 
is very widely extended that cocoa belongs to the very easily digestible foods. The 
extremely favorable mechanical treatment is certainly such that the digestive fluids 
have no considerable mechanical resistance to overcome in the assimilation of the 
nutritive constituents of cocoa. On the contrary, the chemical reaction between 
the solvent constituents of the digestive juices and the nitrogenous nutritive con- 
stituents of cocoa can not be called an especially strong one. <A large proportion of 
these constituents, in spite of apparently favorable conditions, remain entirely in- 
digestible, entirely worthless. I have already called attention to the slight digesti- 
bility of the albuminous substances of cocoa,’ and once illustrated their difficult di- 
gestibility graphically in the Berliner Hygiene-Ausstellung. In the meantime, these 
observations have been confirmed by investigations of H. Weigmann, which he un- 
dertook on his own account. Weigmann found only 42 per cent of the nitrogenous 
substances in cocoa to be digestible. 
1 Op. cit., note 8, p. 958 of this work. 
° Bell, Analysis and Adulteration of Food. 
3 Zeitsch. f. angew. Chem., 1891, 368. 
