Composition of Potatoes used in France for Industrial Purposes.—The following is regarded in France as an average composition of the potato suitable for industrial purposes:[1]
Water, 71.00 percent
Starch, 18.00 "
Sugar, etc., 1.06 "
Cellulose, 1.65 "
Protein, 2.12 "
Fat, .11 "
Ash, 1.60 "
The total fermentable matter, as seen above, is a little over 19 percent, not allowing anything for the cellulose which is fermented. As a portion of the cellulose may also become a source of alcohol, it is observed that the average percentage of fermented matter in the French potato used for industrial purposes is not far from 20 percent.
The following varieties show a variation in starch content of 6.8 percent, the minimum being 15.9 and the maximum 22.7 percent:
Red starchy, 22.7 percent of starch
Shaw, 20.5 " "
Institute of Beauvais, 17.7 " "
Kernours, 17.9 " "
White Elephant, 16.0 " "
British Red, 16.0 " "
Giant Blue, 15.9 " "
Analysis of Potatoes from German Sources.—Average composition and starch content: The content of starch in potatoes examined in the laboratory of the Association of German Spirit Manufacturers during the year 1905 varied from 12.1 to 25.1 percent. Eleven percent of the total number examined contained between 12 and 14 percent of starch, 20 percent between 14 and 16 percent of starch, 13 percent between 16 and 18 percent of starch, 24 percent between 18 and 20 percent, 24 percent also between 20 and 22 percent, and 8 percent between 22 and 25.1 percent.
These data show that 56 percent of the total number of samples examined contained between 18 and 25 percent of starch. It is evident, therefore, that the general average content of starch in the potatoes used in the German distilleries is not far from 18 to 20 percent.
The mean composition of potatoes as given by three German authorities, namely, König, Lintner, and Wolff, is as follows:
Average Analysis of Potatoes by Three German Authorities.
König. Lintner. Wolff.
Constituent. Percent. Percent. Percent.
Water, 75.48 76.0 75.0
Protein, 1.95 2.1 2.1
Fat, .15 .2 .2
Starch and sugar, 20.69 19.7 20.7
Crude cellulose, .75 .8 1.1
Ash, .98 1.2 .9
- ↑ "Encyclopédie Agricole," E. Saillard.
