CH. xxvin.l COOKING OK FOOD. 



sugar from the starch, and then the alcoholic fermentation, due 

 to the action of the yeast, begins. The bubbles of carbonic acid, 

 burrowing passages through the bread, make it light and spongy. 

 This enables the digestive juices subsequently to soak into it 

 readily and affect all parts of it. In the later stages, viz., baking, 

 the temperature is raised, the gas and alcohol are expelled from 

 the bread, the yeast is killed, and a crust forms from the drying 

 of the outer portions of the dough. 



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

 carbohydrates, i of fat, 2 of salts, and the rest water. 



Cooking of Food. 



The cooking of foods is a development of civilisation and serves 

 many useful ends : 



1. It destroys all parasites and danger of infection. This 

 relates not only to bacterial growths, but also to larger parasites) 

 such as tapeworms and trichinae. 



2. In the case of vegetable foods it breaks up the starch 

 grains, bursting the cellulose and allowing the digestive juices to 

 come into contact with the granulose. 



3. In the case of animal foods it converts the insoluble collagen 

 of the universally distributed connective tissues into the soluble 

 gelatin. The loosening of the fibres is assisted by the formation 

 of steam between them. By thus loosening the binding material, 

 the more important elements of the food, such as muscular fibres, 

 are rendered accessible to the gastric and. other juices. Meat 

 before it is cooked is generally kept a certain length of time to 

 allow rigor mortis to pass off. 



Of the two chief methods of cooking, roasting and boiling, the 

 former is the more economical, as by its means the meat is first 

 surrounded with a coat of coagulated proteid on its exterior, 

 which keeps in the juices to a great extent, letting little else 

 escape but the dripping (fat). Whereas in boiling, unless both 

 bouillon and bouilli are used, there is considerable waste. Cooking, 

 especially boiling, renders the proteids more insoluble than they 

 are in the raw state ; but this is counterbalanced by the other 

 advantages that cooking possesses. 



In making //"/ tea and similar extracts of meat it is necessary 

 that the meat should be placed in cold water, and this is gradually 

 and carefully warmed. In boiling a joint it is usual to put the 

 meat into boiling water at once, so that the outer part is coagu- 

 lated, and the loss of material minimised. 



An extremely important point in this connection is that 



K.P. II H 



