40 BULLETIN 1413, U. S. DEPARTMENT OF AGRICULTURE 
The present investigation included chemical examination of rep- 
resentative cocoa press cakes, solvent-extracted cocoas, and cacao 
shells. Several of the samples of press cake satisfied the chemical re- 
quirements for edible cocoa powder. The average calorific value 
of the press cakes was found to be about two-thirds that of good 
bituminous coal; and it has been found feasible to calculate the 
calorific value of the cocoas from their moisture, fat, and ash 
contents, through the employment of a constant determined in this 
investigation. 
More than one-third of the total nitrogen of both the pressed 
cake and solvent-extracted cocoa was found to be water-soluble, but 
the insoluble organic nitrogen, on the basis of its " activity " meas- 
ured b/y either of the permanganate methods, was found to be of 
inferior quality. Also it is shown that the alkaloid nitrogen is 
included in the water-soluble nitrogen, of which it may constitute 
50 to 60 per cent. The sum of the water-soluble and active insoluble 
nitrogen made up a somewhat smaller share of the total nitrogen in 
the cocoa press cakes and extracted cocoas, than in the cases of 
samples of cottonseed meal and castor pomace for which such data 
have been reported in the literature reviewed. 
The cocoa press cakes were found to contain, as the average, 
about three-fourths as much nitrogen and phosphoric acid, and 
twice as much potash as castor pomace; and to be similar to com- 
mercial " cottonseed feed " in crude plant- food content. 
Theobromine and caffeine were found to be present in cocoa 
by-products in quantities significant in relation to use of the mate- 
rials either as feeding stuff or as fertilizer material. Laboratory 
work demonstrated that practically all of the alkaloid in the samples 
examined readily dissolved in water at room temperature. 
Ground cocoa cake is reported to have been satisfactory when 
used as a " rough ammoniate " filler and conditioner in mixed 
fertilizers; and the material had a decidedly higher monetary value 
as fertilizer material than as fuel. Where the cake has been 
marketed for use as an ingredient of mixed feed, it has brought a 
higher price than it commanded as fertilizer material or as raw 
material for the preparation of the alkaloid theobromine. 
It is suggested that an ideal system for the utilization of by- 
product cocoa cake would provide for — (1), recovery of the fat; 
(2), recovery of the alkaloids; and (3), retention of the valuable 
food and fertilizer constituents in the defatted, dealkaloidized 
residue. 
One concern is engaged, commercially, in recovering cacao fat 
from cocoa press cake by solvent extraction; and an important 
quantity of the dried, extracted residue is being produced. Part 
of the output of extracted cocoa has been used as a crude ammoniate 
filler and conditioner in mixed fertilizers, and for this purpose 
the material seems to have been satisfactory to the mixers. 
Eepresentative samples of the factory-made product examined 
show that very nearly the entire content of each of the plant-food 
constituents and of the alkaloids present in the original cocoa cake 
is retained in the defatted by-product, Hence this by-product, 
being nearly fat-free, contains more plant food and has a higher 
value as fertilizer material than average unextracted cocoa. The 
