Chemical and Physical Papers. 201 



THE BAKING QUALITIES OF FLOUR 



As Influenced by Certain Chemical Substances, Milling By-products, 

 and Germination of the Wheat. 



(Abstract). 



By J. T. WiLLARD and C. O. Swanson. 



'T^HE milling tests of wheat and baking tests of flour conducted 

 -*- by the department of chemistry began in 1905, when an ex- 

 perimental reduction mill was purchased. During that year Mr, 

 W. E. Mathewson, in a research conducted as a part of his work for 

 the master's degree, made very careful analyses of several flourp,. 

 including determinations of the percentages of each of the distinct 

 proteids present, and compared their chemical composition with 

 their baking qualities as shown by baking tests made for us in the 

 department of domestic science. At that time the statement was 

 frequently made, and perhaps is, even to-day, that the ratio of the 

 gliadin to the gluteuin of the flour determines its baking qualities. 

 Mr. Mathewson's results threw grave doubt on this supposition, 

 and all subsequent investigations in the department have con 

 firmed the view suggested at that time, namely, that the chemical 

 factors entering into the baking quality of flour are more complex 

 than that. Flours may be very good in their content of gliadin 

 and in the gliadin-glutenin ratio, and yet be inferior in baking 

 qualities to others with supposedly less favorable composition. Of 

 two flours essentially the same in respect to these data, one may be 

 very good and the other very poor. 



As a result of such observations the department has been con- 

 ducting numerous experiments designed to throw light on the sub- 

 ject of baking quality in flour. Many of these do not come within 

 the scope of the present paper, which is concerned with the effects 

 of the addition of certain substances to the flour. These tests were 

 suggested by the thought that, inasmuch as considerable differ- 

 ences in respect to the gliadin and the gliadin-glutenin ratio did 

 not in themselves appear to influence the results much, it might 

 easily be true that the difference in baking qualities exhibited 

 might be caused by substances present in very small amounts. It 

 will be recalled that capacity to produce a good loaf depends on the 

 quality of the gluten that a given flour can yield, other conditions 

 being favorable. Gluten does not exist as such in the flour, but is 

 produced, in a manner not altogether understood, from constitu-^ 



