Chemical and Physical Papers. 85 



A PROPOSED TEST FOR BLEACHED FLOUR. 



By J. T. WiLLARD, Kansas State Agricultural College, Manhattan. 



WITHIN the last three years there has been a great develop- 

 ment of the artificial bleaching or aging of flour. In this it 

 is claimed that the color of the flour is improved and also its bak- 

 ing qualities, so that the treatment gives flour properties that it 

 would naturally acquire on being stored several months. Although 

 boards of health have taken no action concerning this treatment of 

 flour, manufacturers who have not adopted the process and do not 

 wish to go to the expense are claiming that such flour is unwhole- 

 some, and the belief that this is. the case is not uncommonly held 

 by consumers. A simple test to distinguish artificially bleached 

 flour is therefore something to be desired. 



Inasmuch as the bleaching processes in use employ oxids of 

 nitrogen produced in one way or another, it occurred to the writer 

 that Griess's test for nitric acid by means of alphanaphthylamine 

 and sulfanilic acid might be available. In applying this test we 

 have used the modification suggested by Ilosvay, who uses 

 acetic acid instead of mineral acid. One-half gram of sulfanilic 

 acid is dissolved by heat in 150 cubic centimeters of dilute acetic 

 acid. One-tenth gram of alphanaphthylamine is heated with 20 

 cubic centimeters of strong acetic acid, and the colorless solution 

 poured off from the residue and mixed with 130 cubic centimeters 

 of dilute acetic acid. For use, the two solutions are mixed in equal 

 quantities and two cubic centimeters of the mixed solution added 

 to the liquid to be tested. 



In testing flour, about a teaspoonful is shaken with a few cubic 

 centimeters of distilled water and the reagent added directly to it. 

 A pink color of varying intensity is obtained with bleached flour 

 in a few minutes, while unbleached flour gives no reaction. The 

 delicacy of the test is increased by settling out the flour by the use 

 of the centrifuge. 



This test, as will be seen, is very speedy. Its applicability, how- 

 ever, is not yet fully determined, as nitrites are subject to oxidation, 

 and possibly other chemical changes might take place with the 

 lapse of time that would cause failure to react for nitrites. The 

 matter is under further investigation touching this point. 



