324 



Quality in Wheat. 



[SEPT., 



later, its power of resisting the action of the ferments of bread 

 making, are factors in determining the strength of the flour just 

 as much as its quantity. 



More systematic examination of the wheat proteids has been 

 undertaken by Ritthausen, Martin, Osborne and Voorhees, 

 O'Brien, and others, but it cannot be said that the results so 

 far obtained are very consistent in themselves or discriminate 

 clearly between the very complex series of bodies which appear 

 to be present. For practical purposes, however, attention has 

 been concentrated on two of these proteids, gliadin and glutenin, 

 which together, according to Osborne, make up the gluten. 

 Gliadin is a sticky substance soluble in 70 per cent, alcohol, and 

 recoverable on evaporation in thin flakes like gelatin ; glutenin 

 is the tough basis of the gluten, and is insoluble in water, 

 alcohol, and salt solutions, but is soluble in dilute alkali. 

 Girard and Fleurent claimed that the character of the gluten 

 for bread-making purposes was determined by the ratio the 

 gliadin bore to the glutenin, and when estimating the gliadin by 

 using a weak alcoholic solution of potash, they stated that good 

 gluten should consist of about 75 per cent, of gliadin and 

 25 per cent, glutenin. Guthrie in New South Wales and Snyder 

 in Minnesota also determined the gliadin-glutenin ratio for a 

 large number of flours of known strength, and the opinion 

 became generally accepted that in this way a measure could 

 be obtained of the strength of flour. For example, in the 

 Minnesota Agricultural Experiment Station Bulletin No. 63, 

 1899, Snyder states: "A well-balanced gluten is composed 

 approximately of 65 per cent, gliadin and 35 per cent, glutenin. 

 The gliadin-glutenin ratio in the different grades of flour made 

 from the same wheat varies from 27 to 75 in the 'red dog' to 

 63 to 35 in the highest 'patent.' The lower grades of flour 

 contain appreciably more protein than the higher grades, but 

 the gliadin and glutenin in the lower grades are not present in 

 the right proportions to form a well-balanced gluten capable of 

 expansion and able to produce bread of the best physical 

 properties." It should be added that the difference between the 

 ratios suggested by Fleurent and by Snyder is mainly due to the 

 fact that Snyder uses alcohol only and not alcoholic potash for 

 the estimation of gliadin. Many experimenters, however, refused 



