The analysis and adulteration of foods / by James Bell.

  • Bell, James, 1824-1908.
Date:
1881-1883
Catalogue details

Licence: Public Domain Mark

Credit: The analysis and adulteration of foods / by James Bell. Source: Wellcome Collection.

    151/210 (page 137)
    is almost universally made in bakeries wherever the fermentative process of bread-making is followed. Considering the small proportion of potatoes generally used— less than i per cent, of the dry substance—the intention can hardly be said to be that of adding weight to the bread. The object appears to be to cause a more rapid production of saccharine matter by the action of the albuminoids of the flour on the gelatinised starch of the potato—a result which will favour a quicker fermentation, and the production of the necessary carbonic acid gas to form the sponge. Bean or pea flour would only be employed on account of its cheapness, and would add to, rather than detract from, the nutritive properties of the bread; though if used in considerable proportions, there is a danger of imparting an unpleasant flavour to the bread. As pure wheat flour has been found to contain a quantity of alumina equivalent to from 2 to upwards of 40 grains of ammonia alum per 4 lbs., the addition of rice or potatoes to flour would not increase the proportion of alumina. This will be seen from the analysis of rice on page 88, which is shown to be free from alumina, and from the following results obtained from the analyses of four samples of potatoes which had been peeled and boiled in the usual way : Table II.—Analyses of Potatoes. No. Percentage of Water. On the Potatoes dried at 212° F. (100° C. Percentage of Ash. Per 4 lbs. Silica. Phosphate of Alumina. Equivalent Ammonia Alum I 78*99 3*48 2-37 I -90 7'03 2 78*77 4*48 3*29 '94 3'48 3 75*16 3-98 3-15 1*80 6*66 4 7375 2*64 1*70 1*28 4'73