CH. XXVIIL] 



FLOUR 



467 



proteid entirely in the form of meat, it would be necessary for him 

 to consume about 500 grammes (i.e., a little more than 1 Ib.) of meat. 



Flour. 



The best wheat flour is made from the interior of wheat grains, 

 and contains the greater proportion of the starch of the grain and 

 most of the proteid. Whole flour is made from the whole grain 

 minus the husk, and thus c6ntains not only the white interior but 

 also ths harder and browner outer portion of the grain. This outer 

 region contains a somewhat larger proportion of the proteids of the 

 grain. Whole flour contains 1 to 2 per cent, more proteid than the 

 best white flour, but it has the disadvantage of being less readily 

 digested. Brown flour contains a certain amount of bran in addition ; 

 it is still less digestible, but is useful as a mild laxative, the insoluble 

 cellulose mechanically irritating the intestinal canal as it passes along. 



The best flour contains very little sugar. The presence of sugar 

 indicates that germination has commenced in the grains. In the 

 manufacture of malt from barley this is purposely allowed to go on. 



When mixed with water, wheat flour forms a sticky, adhesive 

 mass called dough. This is due to the formation of gluten, and the 

 forms of grain poor in gluten cannot be made into dough (oats, rice, 

 etc.). Gluten does not exist in the flour as such, but is formed on 

 the addition of water from the pre-existing globulins in the flour. 



The following table contrasts the composition of some of the more 

 important vegetable foods : 



We see from this table 



1. The great quantity of starch always present. 



2. The small quantity of fat ; that bread is generally eaten with 

 butter is a popular recognition of this fact. 



3. Proteid, except in potatoes, is pretty abundant, and especially 

 so in the pulses (lentils, peas, etc.). The proteid in the pulses is not 

 gluten, but consists of vitellin and globulin-like substances. 



In the mineral matters in vegetables, salts of potassium and 

 magnesium are, as a rule, more abundant than those of sodium and 

 calcium. 



