Bread-analysis : a practical treatise on the examination of flour and bread / by J. Alfred Wanklyn and W.J. Cooper.

  • Wanklyn, J. Alfred (James Alfred), 1834-1906.
Date:
1886
Catalogue details

Licence: Public Domain Mark

Credit: Bread-analysis : a practical treatise on the examination of flour and bread / by J. Alfred Wanklyn and W.J. Cooper. Source: Wellcome Collection.

    53/96 (page 41)
    Multiply the milligrammes of ammonia by 53-2 and the product will be the number of grains of ammonia-alum contain- ed by the 4Ib loaf. Our experience as public analysts leads us to the conclusion that alumed bread is very rare. Out of some 70 specimens of bread, the analysis of which we have before us, only some 3 or 4 specimens are open to suspicion as being alumed. In taking leave of this portion of our subject we have to advise the public analyst to seek confirmation when a sus]Dicious case arises. An accidental mixing of the flour with a minute quantity of clay — 2 or 3 grains of clay to one pound of flour — would simulate aluming to the extent of 30 grains per 41b loaf; we would therefore urge on the public analyst that he should seek corroboration by having resort to a testing for ammonia and for sulphates. Sulphate of Copper has been employed in bread-making with much the same object as alum, and is effective in even smaller proportion than alum. We consider that this practice should be dealt with the utmost rigour. Fortunately the detection of traces of copper in organic mixtures is exceedingly easy and exceedingly delicate. With the object of detecting traces of copper in flour or bread, 100 grammes should be incinerated in a platinum vessel, the ash moistened with two or three drops of oil of vitriol, and warmed and let cool. Then a little water should be added and a little piece of clean zinc or iron put into the platinum dish containing the liquid. Bye-and-bye if it be present, copper will be deposited on the surface of the pla- tinum dish in the neighbourhood of the piece of zinc or iron, and may be recognised by its red colour. The liquid may then be poured out of the dish, and the spot of copper dis-