TROPICAL FOOD MATERIALS 47 



tion. Certain other advantages of minor importance are also 

 claimed. 



There is very little doubt of the truth of these claims for the 

 superiority of " standard " flour when contrasted with white 

 flour manufactured from the same class of wheat, and with the 

 same care in mixing wheats from different sources, as millers 

 state is the custom at present in order to obtain a strong flour, 

 it is difficult to see how this " standard " flour would not maintain 

 its superiority. In other words, under the same conditions of 

 manufacturing, " standard " flour should show the above-men- 

 tioned points of superiority when contrasted with the ordinary 

 white flour milled from the same source. A " standard " flour 

 obtained from a low-class wheat might in all probability be 

 inferior in nutritive value to ordinary white flour milled from a 

 high- class wheat, and it has been asserted that the " standard " 

 flour allows millers to make use of inferior and injurious wheats, 

 which could not be utilized in the preparation of good white flour. 

 The report, however, of the medical department of the Local 

 Government Board * on the bleaching of flours would show that 

 millers can and do make use of inferior wheats in the production 

 of white flour ; the dark or injured parts can be bleached to 

 represent the finest flour of high-grade wheat. The report states 

 that bleaching with nitrogen peroxide, carefully carried out, in itself 

 produces no appreciable effect upon the baking qualities of flour, 

 but it is capable of improving the colour, and therefore the com- 

 mercial value, of the lower grades of flour, enabling a low-priced 

 article to simulate the appearance of a high-priced one. The 

 reportf goes on to show that the alterations in, and the additions 

 to, flour which result from a high degree of bleaching by nitrogen 

 peroxide cannot be regarded as free from risk to the consumer. 

 It is demonstrated that there is a certain amount of nitrite- 

 reacting material present in bleached flour, one of the effects of 

 which is to cause interference with digestion. Thus, Halliburton 

 found that traces of nitrites exert a distinct inhibitory effect on 

 both proteolytic and amylolytic enzymes, 1 part of sodium 

 nitrite in 8,000 inhibiting peptic digestion entirely, while 1 part 

 in 32,000 decreased the power of the enzymes to one-seventh of 

 its normal activity ; similar results were obtained in the case of 

 the salivary digestion of starch. Hale has found that sodium 



* Reports to the Local Government Board on Public Health and Medical 

 Subjects, Nos. 46 and 47. 



f " The Purity of Flour and Bread," British Medical Journal, vol. i., 1911. 



