DIGESTIBILITY OF THE GRAIN SORGHUMS. 21 



Summary of digestion experiments with wheat bread in a simple mixed diet. 



Experi- 

 ment No. 



Subject. 



Protein. 



Carbo- 

 hydrates. 



Experi- 

 ment No. 



Subject. 



Protein. 



Carbo- 

 hydrates. 



226 



227 



228 



D. G. G :.. 



R. L. S 



O.E.S 



Per cent. 

 73.0 

 88.8 

 66.4 



Per cent. 

 93.6 

 98.1 

 93.2 



229 



R.F.T 



Average. . 



Per cent. 

 81.0 



Per cent. 

 96.4 



77.3 



95.3 



The digestibility of fat and carbohydrate in both the corn and the 

 wheat bread diets was very satisfactory, 94.5 per cent of fat and 95.9 

 per cent of carbohydrate in the ration containing corn, and 94.1 per 

 cent of fat and 95.4 per cent of carbohydrate in the wheat diet 

 representing the percentages of available nutrients. The estimated 

 value for the digestibility of the carbohydrate of corn bread alone is 



96.2 per cent and of the carbohydrate of wheat bread 95.3 per cent. 

 An average of 38.4 grams of protein per man per day was 61.8 per 



cent digested in the experiments with corn bread and, although the 

 average daily consumption of protein in the experiments with wheat 

 was only 53.3 grams, this was 76.0 per cent available to the body. 

 The estimated digestibility of the protein supplied by the corn bread 

 alone is 59.9 per cent, and of the protein supplied by wheat bread 



77.3 per cent. These values undoubtedly vary with the quantity of 

 bran present in the flour and with other experimental conditions, 

 such as the nature of the diet and the quantity of protein eaten. 

 This opinion is in accordance with the conclusions of other investi- 

 gators. Results of experiments by Woods and Merrill, 1 conducted 

 in cooperation with the earlier work of the Office of Home Economics, 

 indicate that all kinds of wheat bread are well digested and deserving 

 of the important place given to them in the diet. These investi- 

 gators found that the digestibility of the protein of wheat bread 

 varied from 93.8 per cent for standard patent to 80 per cent for 

 entire wheat flour. Snyder 2 also studied the comparative digesti- 

 bility of protein in different grades of wheat flour, finding that 

 although the entire wheat and graham flours contained more protein 

 than the patent flours, the percentages of protein actually available 

 to the body was greater in the patent flour. In experiments with 

 Indian corn meal prepared for eating in several different ways, 

 Merrill 3 found a digestibility of protein varying from 73 to 86 per 

 cent. 



The digestibility of corn protein herein determined, 59.9 per cent, 

 is somewhat lower than that usually reported, but it seems reasonable 

 to conclude, in comparison with the preceding experiments with the 

 grain sorghums in identically the same basal ration, that corn protein 

 is more thoroughly digested than are the protein constituents of dwarf 



i U. S. Dept. Agr., Office Expt. Sta. Bui. 143 (1904), p. 33. 2 Maine Sta. Bui. 131 (1906). 

 s Idem,126 (1903), p. 46; 156 (1905^. 



