Chemical Notes on Wheat and Flour. 339 



gluten is obtained by a trial baking ; but some more rapid 

 and convenient test is desirable, and to be of service to the 

 baker in valuing his flour for strength must in character 

 approximate to baking. An excellent test consists in ex- 

 posing the gluten under proper conditions to such a tem- 

 perature that the moisture of the moist gluten is vaporised, 

 and in process of vaporisation and escape, expands the 

 gluten. A soft, inelastic gluten readily allows the steam to 

 pass out from the mass, whilst a firm, elastic gluten pre- 

 sents greater resistance to the steam, and is therefore 

 expanded to a greater extent. The higher the quality of 

 the gluten, the greater the expansion it undergoes. 



I have yet to refer to the effect of frost on grain, and on 

 the flour produced from such grain. This is an important 

 point, inasmuch as for several seasons (excepting harvest 

 of 1886) the wheat in many parts of the Noi'thwest was 

 injured by frost, and the Northwest is the great wheatfield 

 of Canada, the feeder of the numei-ous mills in this and the 

 adjacent Province of Ontario. 



The effect of frost is seen in the bluish color and shriv- 

 elled appearance of the grain ; the flour from such wheat is 

 poor in gluten, and the quality of the diminished gluten is 

 low. I am unable to indicate the precise changes which 

 the constituents of the grain have undergone as result of 

 being frozen. It seems that both the starchy and albu- 

 minoid matters of the grain are affected by frost. It seems 

 probable that the frost directly acts upon the albuminoids, 

 and through them upon the starch. 



A sample of flour from frozen wheat yielded only 25 p.c. 

 moist gluten, whilst flours obtained from similar wheats 

 which had not been frozen, gave on analysis 27 and 28 p.c. 

 moist gluten. Not only does freezing diminish the amount 

 of gluten in the wheat, but it also affects the quality of the 

 gluten. In flour from frozen wheat, the total amount of 

 matter extracted by cold water in half an hour was 5 . 58 

 p.c, whereas in a sample of same grade from sound wheat, it 

 was only 4.60 p.c, i.e., flour from frozen grain had nearly 

 25 p. c more matter soluble in water than that from 

 sound flour. The soluble albuminoids of the frozen amounted 



