FOODS 41 



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

 the addition of water from the pre-existing soluble proteids {e.g. 

 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 (lentUs, peas, &c.). The proteid in the pulses is not 

 gluten, but consists of vitellin and globuUn-Uke substances. 



In the mineral matters in vegetables, salts of potassium and 

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

 calcium. 



BREAD 



Bread is made by cooking the dough of wheat flour mixed with 

 yeast, salt, and flavouring materials. A ferment in the flour acts at 

 the commencement of the process when the temperature is kept a 

 httle over that of the body, and forms dextrin and sugar from the 

 starch, and then the alcohoHc fermentation, due to the action of the 

 yeast, begins. The bubbles of carbonic acid, burrowing passages 

 through the bread, make it Ught and spongy. This enables the 

 digestive juices subsequently to soak into it readily and affect all 

 parts of it. During baking the gas and alcohol are expelled from the 

 bread, the yeast is kUled, and a crust forma from the drj-ing of 

 the outer portions of the dough. 



White bread contains, in 100 parts, 7 to 10 of proteid, 55 of carbo- 

 hydrates, 1 of fat, 2 of salts, and the rest water. 



COOKING OF FOOD 



The cooking of foods is a development of civilisation, and much 

 relating to this subject is a matter of education and taste rather than 



