12 BULLETIN 666, U. S. DEPAKTMENT OF AGRICULTURE. 



As might be expected, the ash of the soluble matter varies about 

 the same as the ash of the cocoa. 



The water-soluble protein is slightly higher in the alkali-treated 

 cocoas than in the untreated cocoas, the maximum percentage 

 being 0.51 higher, and the average 0.44 higher. The percentage of 

 water-soluble protein insoluble hi 1 per cent sulphuric acid, however, 

 seems to be an important determination. In every case where the 

 cocoa had been treated, more or less nitrogenous matter was precipi- 

 tated by the addition of 1 per cent of sulphuric acid to the water- 

 solution of the cocoa. This nitrogenous matter, calculated as pro- 

 tein, ranged from 0.38 to 5.12 per cent. The total water-soluble pro- 

 tein was not increased by any such figure. This would tend to show 

 either that the alkali treatment inhibited the solution of some of the 

 nitrogenous substances which would normally be dissolved by the 

 water, or that some substance was dissolved by the alkali, which on 

 the addition of sulphuric acid had precipitated some of the protein 

 which was normally water-soluble. The untreated cocoas showed 

 no precipitate on the addition of 1 per cent of sulphuric acid, the 

 only exceptions to this being samples 1, 13, and 29, which have 

 already been set aside on the ground that they were more or less con- 

 taminated with alkali-treated cocoas, having been made in a fac- 

 tory which also makes alkali-treated cocoas and passed through the 

 same machinery. In no case where the sample was made by a firm 

 which makes no alkali-treated cocoa was there any precipitate. 



As might have been expected, the alkali treatment greatly en- 

 hanced the color of the water solution. The color values of the 

 untreated cocoas ranged from 20 to 39.3, with an average of 27.4, 

 those of the treated cocoas from 25.5 to 98.4, with an average of 64.7. 

 Only three of the alkali-treated cocoas showed a color value of less 

 than 46.4, and 16 showed a color value of over 60. The maxi- 

 mum of the alkali-treated cocoas was 59.1 above the maximum for 

 the untreated cocoas, and the average was 37.3 above the average 

 for the untreated cocoas. 



Samples 1 and 2, representing the same blend of cocoas, sample 1 

 being untreated and sample 2 treated with 2.5 per cent potassium 

 carbonate, show the effect of treatment. The total water-soluble 

 matter, the water-soluble matter less the ash, the water-soluble pro- 

 tein, and the color value are increased by the alkali treatment. The 

 nonnitrogenous, nonash soluble solids, however, are found in large 

 amount in the untreated cocoa. Samples 15 and 11 represent the 

 same blend of beans and the same alkali, but, in addition to the alkali, 

 sample 15 had added to it 10 per cent of water in the treatment. This 

 water treatment largely increased the soluble matter and deepened 

 the color. Sample 16 was made with 1.5 per cent potassium car- 

 bonate and 1.5 per cent sodium carbonate, while sample 12 was made 

 with 2.5 per cent potassium carbonate. The mixed carbonates in- 



