32 BULLETIN 1413, U. S. DEPARTMENT OF AGRICULTURE 
Most, if not all, of the potash is retained and recovered in the 
extracted residue. This is accounted for by the fact that the water 
with which the cocoa becomes mixed during the extraction opera- 
tion is absorbed by the cocoa matter and the dissolved salts remain 
with the sludge when the latter is dried. In view of this retention 
of plant-food elements, and the elimination of most of the fat, 
the dried solvent-extracted cocoa undoubtedly has a higher value 
as fertilizer than unextracted cocoa. 
The retention of the theobromine and caffeine in the sludge is 
explainable on much the same grounds as the retention of the 
mineral salts. Theobromine is far more soluble in water than in 
benzol, according to Wadsworth (55), and it appears that little if 
any alkaloid is lost from the cocoa matter in the solvent-extraction 
of the fat. Although the retention of the alkaloids in the extracted 
cocoa creates a certain value for the product as raw material for 
the preparation of theobromine, the presence of the alkaloids is an 
obstacle to utilization of the product as a feed stuff and detracts 
from its intrinsic value as a source of plant food. 
The permanency of the commercial production of solvent-ex- 
tracted cocoa depends, of course, on the ability of the extraction 
industry to continue to solve the major problems as they appear. 
One of the problems that is receiving attention is that of finding 
more profitable outlets for marketing the defatted cocoa by-product. 
As pointed out above, the dried extracted cocoa obviously has a 
higher value for use as fertilizer material than the unextracted 
cocoa cake, as it contains more total ammonia, potash, and phos- 
phoric acid, and is nearly free from the undesirable fat. Compari- 
son of the data on the solubility and quality of the nitrogen ot the 
sample dried at 100° C. and the kiln-dried sample (Nos. 106-A and 
107, Table 3) indicates, however that the quality of the factory 
product could be somewhat enhanced by drying at lower tempera- 
tures to avoid charring. It appears, therefore, that one opportunity 
for improving the marketability of the extracted cocoa by-product 
lies in devising means for dehydrating the sludge at lower tempera- 
tures, but at a cost commensurate with the commercial value of 
the product. 
The theobromine and caffeine content of the dried extracted 
cocoa is shown by the data in Tables 2 and 4 to be about on par 
with that of the by-product cocoa cake. This fact, together with 
the low fat content of the solvent-extracted material, suggests that 
it is very well suited for use as raw material for the preparation 
of theobromine alkaloid. "With the process now in use for the com- 
mercial production of theobromine, the presence of fat in the raw 
material is undesirable. 
The materials used at present as a source of theobromine, with 
which the extracted cocoa would have to compete In this field, are 
the by-product press cake and cacao shells. Dry-pressed cocoa cake 
is preferred to the commercial shells, in spite of its somewhat 
higher fat content, because it usually contains from 50 to 100 per 
cent more of the alkaloid than the shells. 30 Obviously, the dried, 
cxtracted-cocoa residue would occupy a very advantageous position 
30 Wads-worth (~>7) reports Iho average theobromine content of 31 samples of separated 
cacao shells as 1.27 per cent, and that of commercial cocoa powders (23 samples) as 2.10 
per cent. Many investigators have reported the theobromine content of cacao shells to 
be under 1 per cent. 
