43 



Considerincr the averages of the exporiinents with l)otli kinds of 

 flour, the dio-estibility of the bread from the flour with the bran was, 

 for protein 85.9 per cent and for carbohydrates 93. A per cent, whereas 

 that of the bread from the same flour without the bran was. for pro- 

 tein 90.9 per cent and for carbohydrates 97.7 per cent. The inference 

 from these results is that the addition of the flnely g-round bran 

 decreased the digestibility of the product. . 



Though the bran flour contained a larger percentage of protein than 

 the flour without the bran, in consequence of its lower digestibility the 

 nutritive value of the former was actually less, as will be apparent 

 from a comparison of the data summarized in the following table, 

 showing the percentages of total and digestible nutrients and the total 

 and available energy per gram in both kinds of flour: 



Table 30. — Comparison of total and digestible nutrients and total ami available energy in 



the same flour with and without bran. 



There was a larger percentage of total protein and a smaller per- 

 centage of total carbohydrates in the flour with the bran than in that 

 without it; but comparing the digestible nutrients it will })e observed 

 that what little was gained in total amount added by including the 

 finely ground bran was more than lost in the decreased digestibility 

 due to the addition of the bran, the proportions of digestible nutrients 

 and available energv being larger in the flour without the bran added. 

 This means that from the .same amounts of both kinds of flour the 

 bod}' would actually derive more nutrients and energv from the flour 

 without the bran in spite of the fact that the amount of protein is 

 larger in the flour with the bran added. 



It is interesting to compare the average values for the digestil)ility 

 of Graham and entire-wheat flours, that is, flours normally containing 

 more or less coarse bran, with the average results obtained in diges- 

 tion experiments with straight-grade patent flour to which flnely 

 ground bran was added. Such a comparison is made in the following- 

 table, wliich also shows the digestibility of .straight-grade flour: 



Table 81. — Xutrieuts digested from bread from different kinds of flour. 



Kind of flour. 



Protein. Carbo^by. 



drates. 



Graham flour 



Entire wheat flour 



Straight-grade flour with bran added 

 Straight-grade flour 



