WINNIPEG, 1909. 781 
that the ratio of gliadin to glutenin, or the ratio of gliadin to the total 
protein in the flour, influences the quality of gluten and affords a measure 
of strength. Girard and Fleurent suggested the proper proportion of gliadin 
to be 75 per cent. of the gluten. Snyder fixed the ideal ratio at 65 per 
cent., but experience has not supported these views; the gliadin ratio is 
erratic and apparently of little value for diagnostic purposes. A. D. Hall 
has adversely criticised the determination of the percentage of gliadin as 
an indication of strength; F. T. Shutt considers it to be more valuable, 
and suggests there is an indication of a relationship between the maturity 
of the grain and the gliadin content. The more fully ripened wheat 
contains the higher proportion of gliadin. The subject evidently demands 
further study. 
Proteins of Flour. 
As already indicated, wheat contains more than one protein. Gliadin 
and glutenin make up about 90 per cent. of the total protein matter of 
the seed; this in addition contains lewcosin, a so-called albumen, which 
is freely soluble in water and coagulates when the solution is heated. In 
gluten the gliadin acts as the sticky binding substance, whilst the glutenin 
serves to fill up the network of gliadin threads. 
These two proteins were thought at one time to have a common origin 
or to be derived from one another when flour is wetted. Osborne, who has 
studied the products of their complete hydrolysis, finds that gliadin differs 
sharply from glutenin in yielding. no glycine and no lysine; it also gives 
nearly twice as much proline as glutenin. 
Both gliadin and glutenin, which yield 37 and 23 per cent. of glutamic 
acid respectively, differ greatly from leucosin, which gives only 6 per 
cent, of this acid. They both give rise to considerable quantities of 
ammonia, whereas leucosin yields but little ammonia. 
The substances mentioned as decomposition products of gliadin and 
glutenin all belong to the ‘ amino acids’ which modern research has shown 
to make up the greater portion of the protein molecule. 
T. B. Wood has carried out experiments which indicate that gliadin 
derived either from strong or weak wheats is the same in each case. 
Osborne’s very careful researches all show that the proteins of wheat are of 
constant composition independent of their origin. 
To sum up: whereas, broadly speaking, strength must be associated with 
the total quantity of gluten or nitrogen in a flour, yet it is the physical 
properties of gluten, rather than the amount, which determine the behaviour 
of the flour in bread-making. 
Sugar. 
The distention of the loaf is due to the gas formed during panary 
fermentation from sugar. The amount of sugar actually present in flour 
would not suffice to give the necessary volume of gas but it is supplemented 
by sugar produced from the starch of the flour. The formation of sugar 
is effected by the agency of a diastatic enzyme; it begins directly the flour 
is wetted and continues throughout fermentation until the loaf is baked. 
In general, therefore, the presence of more or less sugar in a flour is 
unimportant and the percentage shows no relationship with the volume 
of the loaf. 
Diastatic Enzyme. 
Obviously, there must not only be a plentiful supply of gas available 
to distend the loaf but also to maintain it fully distended until it is fixed 
in the oven. Flours which have relatively little diastatic enzyme will 
produce insufficient gas. A deficiency of diastase has been actually proved 
to occur in many flours tested, or at all events better loaves have been 
