“—™ 
Washington, D. C. February 28, 1924 
DIGESTIBILITY OF RAW STARCHES AND CARBOHYDRATES. 
By C. F. Laneworray, Specialist in Calorimeter Experiments, and AtickE THompson 
MERRILL, Specialist in Digestion Experiments, Bureau of Home Economics. 
CONTENTS 
Page. Page 
_aperimental method.......:...-.---------- 2 | Experiments with raw graham flour. .....-.- 10 
Experiments with raw cornstarch .......---- 4 | Experiments with raw farina...............- 11 
Experiments with raw wheat starch......-.- 5 | Experiments with raw white corn meal. . ... 12 
Experiments with raw rice starch..........- 6 | Experiments with raw waxy maizemeal.... 13 
Experiments with raw potato starch.....---- MOMSUMEM ALY 255 Sachem secre ee noes ein cne eee 15 
Experiments with raw patent flour..-..----- 8 
The digestibility of over 100 different food materials has been 
tested in this department by feeding experiments with normal men.! 
Throughout the work a uniform method has been followed, so that 
the results obtained with the different materials are directly compara- 
ble. It has been commonly assumed that the coefficients of digest- 
ibility determined in such experiments with men as subjects are 
equally applicable in the case of normal women and children, but 
nothing has been found in the literature to indicate that this has 
been proved experimentally. 
The first four of the eight series of experiments here reported were 
oxen primarily to test this point. Previous experiments with men 
ad shown that raw corn, wheat, and rice starches were completely 
assimilated without noteworthy physiological disturbance. Raw 
potato starch, however, taken in the same quantity as the other 
starches was not completely digested, and the subjects experienced 
discomfort while on the experimental diet. When raw potato starch 
‘was eaten in smaller quantities the coefficient of digestibility was 
higher. This work was accordingly repeated with practically no 
change save that women instead of men served as subjects. In two 
other series of the present experiments the materials used, raw pat- 
ent and raw graham flour, though not in exactly the same form as in 
previous experiments with men, were sufficiently similar to indicate 
relative digestibility with normal men and women. 
The main purpose of the present experiments with raw flours was 
not, however, to show whether or not sex affected the digestibility, 
1U.S. Dept. Agr. Buls. 310 (1915), 470 (1916), 505 (1917), 507 (1917), 525 (1917), 612 (1917), 613 (1919), 630 
(1918), 649 (1918), 687 (1918), 717 (1918), 751 (1919), 781 (1919), 1033 (1922). Jour. Agr. Research 6 (1916), 
No. 16, p. 577-588; 6 (1916), No.17, p. 641-648. Jour. Biol. Chem. 41 (1920), No. 2, p. 227-235; 42 (1920), No. 
1, p. 27-40; 52 (1922), No. 1, p. 251-261. Jour. Ind. & Eng. Chem. 12 (1920), No. 10, p. 975. Amer. Jour. 
Physiol. 54 (1921), No. 3, p. 479-488. Jour. Home Econ. 15 (1923), No. 12, p. 699-701. 
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