20 BULLETIN 666, U. S. DEPARTMENT OF AGRICULTURE. 



to a lesser degree, in a great number of the other cocoas. In some 

 cases a cocoa which seems to be of a quite light color when dry shows 

 a very high color in the water solution. The color developed in the 

 cocoa depends, of course, somewhat on the blend of beans used, but 

 to a greater extent on the treatment which the product undergoes. 



CONCLUSIONS. 



The greatest effect of the alkali treatment of cocoas is apparently 

 the increase in the color of the water solution. The total water- 

 soluble matter is increased but slightly, and this increase is more than 

 accomited for on the ground of the addition of the soluble alkali, the 

 ash-free soluble matter being less in the case of an alkali-treated cocoa 

 than hi the case of the untreated cocoas. There is a slight increase in 

 the amount of water-soluble protein by the alkali treatment. This, 

 however, is more than made up for by the fact that the alkali treat- 

 ment exercises an mhibitory action on the solution of the non- 

 nitrogenous substances which are normally soluble in water. A 

 portion of the water-soluble protein of the alkali-treated cocoas seems 

 to be different from that dissolved in the untreated cocoas, inasmuch 

 as it is rendered insoluble when the water solution is made 1 per cent 

 acid with sulphuric acid. This is a point of difference between alkali- 

 treated and untreated cocoas which might well serve for the detection 

 of the alkali treatment. 



As has been pointed out by other investigators, the alkali treat- 

 ment increases the ratio of the soluble ash to the insoluble ash. This 

 is true with all the alkalies employed, except ammonium carbonate 

 and magnesium carbonate. Both of these, however, increase this 

 ratio in the ash of the water-soluble matter, and this determination 

 might serve as a clue to their presence. The ratio of the alkalinities 

 of the ashes is still more pronounced than the ratio of the ash. The 

 presence of an alkali-treated cocoa may therefore be proved by the 

 high color value of the water solution, by the presence of a water- 

 soluble protein precipitable in 1 per cent sulphuric acid, and by the 

 increase in the ash ratios and the alkalinity ratios. 



This investigation proves that the claim that the alkali treatment 

 increases the amount of cocoa soluble in water is absolutely without 

 foundation. 



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