47 



hydrates, and 1 ^ram of the tiour yielded 3. •545 caloi-ies of available 

 energj'. The entire-wheat flour prepared from the same wheat yielded 

 10.82 per cent digestible 'protein, 66.87 per cent digestible carbo- 

 hydrates, and 3.375 available calories per gram. The difference in 

 digestible protein is small, being 0.11 per cent in favor of the mixed- 

 grade flour. The difference in. the digestible carbohydrates is quite 

 large, being 6.24 per cent in favor of the mixed-grade flour. The 

 difference in the available energy is also large, amounting to 0.261 

 calorie per gram in favor of the white flour. 



While there is no material difference as to the amount of digestible 

 protein in the two kinds of flour, the differences in digestible carbo- 

 hydrates and available energy are decidedly in favor of the mixed-grade 

 flour. The entire-wheat flour contained a larger amount of protein, 

 but, as shown in Table 34, this protein is less digestible than that of 

 the mixed-grade flour, wdiich was more finely granulated. 



The straight-grade flour prepared from the Michigan wheat con- 

 tained 10.13 per cent digestible protein, 75.61 per cent digestible 

 carbohj-drates, and 3.574 calories of available energy per gram. Com- 

 pared with graham flour, this shows 0.4 per cent of digestible protein, 

 10.18 per cent of digestible carbohvdrates, and 0.353 calorie of avail- 

 able energy per gram in favor of the white flour. Compared with 

 the entire-wheat flour, the results show a difference of 6. si per cent 

 digestible carbohvdrates and 0.180 available energy per gram in favor 

 of the straight-grade flour; the difl'erence in digestible protein, though 

 too small to be of significance, is 0.16 per cent in favor of the entire- 

 wheat flour. In the description of the samples it was stated that the 

 straight-grade flour did not contain all of the granular middlings 

 which are usuall}" included in the preparation of ordinary straight 

 flours. Had the flour contained the granular middlings, the percent- 

 age of protein, it seems fair to conclude, would have been higher than 

 10.92. While the difference in total protein is 1.1 per cent in favor of 

 the entire-wheat flour, the higher degree of digestibility of this con- 

 stituent in the straight-grade flour makes the figures for the total 

 digestible protein in the two kinds of flour practically the same. 

 Hence, what is gained from the somewhat larger amount of protein in 

 the entire-wheat and graham flours is lost in digestibility. While the 

 difl'erence between the digestible protein in the straight-grade and 

 entire-wheat flours prepared from the same lot of soft wheat is small, 

 the difference in digestible carbohydrates is large, being 6.8 per cent 

 in favor of the white flour. Since a larger amount of digestible carbo- 

 hydrates and available energy is secured from the mixed and straight- 

 grade flours than from the entire-wheat flour and no appreciable 

 differences were observed as to digestible protein, it would appear 

 that a larger total amount of nutrients and energy is available to the 



