Shell contains about one per cent. of theobromine (dimethylxanthine). This is a very valuable chemical substance (see remarks in chapter on [Food Value of Cocoa and Chocolate]), and the extraction of theobromine from shell is already practised on a large scale, and promises to be a profitable industry. Ordinary commercial samples of shell contain from 1.2 to 1.4 per cent. of theobromine. Those interested should study the very ingenious process of Messrs. Grousseau and Vicongne (Patent No. 120,178). Many other uses of cacao shell have been made and suggested; thus it has been used for the production of a good coffee substitute, and also, during the shortage of sawdust, as a packing material, but its most important use at the present time is as cattle food, and its most important abuse as an adulterant of cocoa.
The value of cacao shell as cattle food has been known for a long time, and is indicated in the following analysis by Smetham (in the Journal of the Lancashire Agricultural Society, 1914).
ANALYSIS OF CACAO SHELL.
| Water | 9.30 |
| Fat | 3.83 |
| Mineral Matter | 8.20 |
| Albuminoids | 18.81 |
| Fibre | 13.85 |
| Digestible Carbohydrates | 46.01 |
| 100.00 |
From these figures Smetham calculates the food units as 102, so that it is evident that cacao shell occupies a good position when compared with other fodders:
FOOD UNITS.
| Linseed cake | 133 |
| Oatmeal | 117 |
| Bran | 109 |
| English wheat | 106 |
| Cacao shells | 102 |
| Maize (new crop) | 99 |
| Meadow hay | 68 |
| Rice husks | 43 |
| Wheat straw | 41 |
| Mangels | 12 |
These analytical results have been supported by practical feeding experiments in America and Germany (see full account in Zipperer's book, The Manufacture of Chocolate). Prof. Faelli, in Turin, obtained, by giving cacao shell to cows, an increase in both the quantity and quality of the milk. More recent experience seems to indicate that it is unwise to put a very high percentage of cacao shell in a cattle food; in small quantities in compound feeding cakes, etc., as an appetiser it has been used for years with good results. (Further particulars will be found in Cacao Shells as Fodder, by A.W. Knapp, Tropical Life, 1916, p. 154, and in The Separation and Uses of Cacao Shell, Society of Chemical Industry's Journal, 1918, 240). The price of shell has shown great variation. The following figures are for the grade of shell which is almost entirely free from cocoa: