12 The Composition and Food Value of Bread. 



In this tahle tbe analyses illustrate the comparative 

 composition of varioiis types of flour, all made from the 

 same blend of wheat. The figures show clearly that what 

 are known commercially as higher grade flours contain less 

 protein and less phosphoric acid than the flours of the com- 

 mercially lower grades made from the same blend of wheats, 

 and that the offals contain far more protein and far more 

 phosphoric acid than any of the grades of flours. For obvious 

 reasons the offals themselves cannot be used for bread making. 

 Confining our attention to the various grades of flour, it appears 

 from the figures that the more particles of husk the flour 

 contains, in other words the lower its commercial grade, the 

 higher its proportion of protein and phosphoric acid. It has 

 already been pointed out that the diet of the working classes 

 of this country appears to be deficient in protein, and at first 

 sight it seems reasonable to assume that the numerous attempts 

 which have been made to replace bread made from flours of 

 commercially high grades by bread made from flours of 

 commercially low grades, are well founded and likely to lead 

 to improvement in the diet of the people. 



Before this assumption can be finally accepted it is necessary 

 to inquire more fully what happens to bread inside the body. 

 A piece of bread when taken into the moiith is first submitted 

 to the process of chewung or mastication. Whilst chewing 

 proceeds saliva is poured into the mouth by the salivary glands. 

 The piece of bread is divided into very small particles by the 

 teeth, and mixed into a paste as it is moistened by the saliva. 

 The digestive ferment of the saliva begins to convert some 

 of the starch of the bread into sugar. As soon as the whole 

 mouthful of bread is m.oistened it is collected by the tongue 

 into a mass, passed to the back of the moiith and swallowed. 

 In this way it reaches the stomach, where it is submitted to 

 •the digestive action of the gastric juice, the ferment of which 

 begins to dissolve some of the protein and phosphates of the 

 bread. Digestion, however, is not completed in the stomach. 

 The bread, which is now finely divided and mixed into the 

 consistency of cream, is passed on into the small intestine, 

 where it meets with the digestive juices of the liver and of the 

 pancreas. These juices, the bile and the pancreatic juice, 

 contain ferments which continue the actions l)egun by the 

 saliva and the gastric juice, converting more of the starch into 

 sugar, and dissolving more of the protein. As the semi- 

 digested food passes onwards through the intestine, this process 

 continues, and the digested sugar and protein are absorbed 

 into the blood which circulates in the intestinal walls, and 

 carried by the blood to the various tissues of the body. Only 

 that poi'tion of the food which is thus dissolved and absorbed 



