lo April, 1912.] 



11 '//<■(?/ and its Cultivation. 



a 70 per cent, solution of alcoh il. If thi.s ."-olution be filtered and care- 

 fu Iv" evaporated, the gliadin may be obtained in tran.sparent laminae. 

 Ths gliadin forms with water a sticky medium, and it helps to bind the 

 particles of flour toge:her, making the di^ugh tough and cohen?nt. 



The glu'enin imparts solidity to the gluten and evidently forms a 

 nucleus to which the gliadin adheres. It is distinguished from gliadin 

 -by being nr.n-adhesive and ncn-plastic, and by the fact that it is in- 

 .'oluble in dilute alcohol. These two proteids together constitute the 

 gluten of wheaten flour, and it is owing to the presence of this gluten that 

 it becorr.es possible to make a porous bread from flour. The carbonic 

 acid gas evolved during the fermentative action of the yea.st becomes im- 

 prisoned in the gluten, and the expansion of this gas during leavening 

 and baking causes the bread to " rise " and become light and porous. 

 The gliadin and glutenin together amount to 80-90 per cent, of the total 

 prjteids of the wheat kernel. 



It i.s founil that the amount of gliadin compared v'lth glutenin varies 

 very considerably in d fferent wheats, and, on this account, it was for- 

 merlv suggested that what is known as strength in wheat was dependent 

 on the gliadin-glutenin ratio. Subs?quent investigations, however, have 

 failed to estab'ish any relation between the strength and the gliadin- 

 glutenin ratio. 



It may 1 e mentioned that the gliadin-glutenin ratio of four different 

 samples of Federation wheat from the Parafield Wheat Station in 1909 

 was found by the writer to be 42 : 58. The gliadin-glutenin ratio in 

 these samples was not connected by any definite relation to the strength 

 -or other physical properties of the flour. This may be seen from Table 

 v.* The four samples of wheat referred to were all samples of Federa- 

 tion. Grade I. consisted of fine plump grain weighing 68J lbs. y.ex 

 bushel, obtained by sieving a parcel of wheat with a mesh of .275 cm. 

 Grade II. we"ghed 67! lbs. per bushel, and was composed of grains 

 passing through a .25 cm. sieve, but retained by a .225 cm. mesh. 

 Grade III. weighed 63 lbs. per bushel and was obtained with a .2 cm. 

 sieve, wh'lst ihe lowest grade was hand-picked from shrivelled grain which 

 passed through the .2 cm. sieve. 



Taf)le V. summarizes the densitv. volume, and milling products of each 

 grade of wheat and the gliadin-glutenin ratio and strength of the resultant 

 flours. 



TABLE V. 



Vide " Milling Qualities of High and Low-grade Wheats" by A. E. V. Richardson. 

 S.A. Djpartm^nt of Agriculture. 



Bulletin Xo 61. 



