214 III. DIGESTIBILITY OF FATS 



Table 8 



Tests with Dogs Illustkating Calculation of the Digestibility of Fat and 



Stearyl Citrate When Fed Together" 



Results on 

 Category dog 10 



Food eaten, g 968.0 



Fat eaten, g 196.5 



Stearyl citrate eaten, g 29 . 1 



Feces: 



Dry weight, g 103 . 7 



Corrected dry weight, g. (Corrected by subtracting weight of stearyl 

 citrate plus stearyl alcohol (item o, Table 6) from total weight of 



dried feces 87 . 7 



Lipid excreted: 



Neutral fat, g 35 . 8 



Soaps, g 12.1 



Total, g 47.9 



Corrected for stearyl citrate and stearyl alcohol only, g 31 . 9 



Corrected for stearyl citrate, stearyl alcohol, and metabolic fat, 



g 145 



Coefficients of digestibility 



Total lipid 75.6 



Fat 



Corrected for stearyl citrate, and stearyl alcohol only, g 83 . 8 



Corrected for stearyl citrate, stearyl alcohol, and metabolic fat, g. . . 92 . 6 



Stearyl citrate alone 45 . 



° C. E. Calbert, S. M. Greenberg, G. Kryder, and H. J. Deuel, Jr., Food Research, 16, 

 294-305(1951). 



antly, if the undigested residue of the test substance can be determined 

 in the N.S.F. Similarly, the same procedure can be applied to waxes if 

 the proportion of the wax which has been hydrolyzed can be ascertained. 



The steps in the calculation of the digestibility of the higher alcohol 

 (stearyl alcohol) have been summarized by Calbert et al. 7 as follows: 



A. Calculation of digestibility of total lipid by the usual methods 39 



B. Calculation of digestibility of fat alone 



a. Determination of total fat fed 



b. Total fat excreted = total fecal lipids - [metabolic lipid + N.S.F. (corr.)*] 



c. Digestibility of fat alone = (a — b)/a X 100 



C. Calculation of digestibility of alcohol* alone 



d. Determination of total alcohol fed 



e. Alcohol excreted = total N.S.F. excreted — control N.S.F. excreted 



f. Digestibility of alcohol = (d - e)/d X 100 



° Metabolic lipid is determined by total lipid excretion (neutral fat -+- soap) on fat- 

 free diet. 



b Non-saponifiable fraction (corr.) = total fecal N.S.F. - N.S.F. of control groups. 

 c Applies only to higher alcohols which are not water-soluble. 



The calculation to be used for determining the digestibility of the fat 

 separately, or of the higher alcohol alone, is similar if a higher hydro- 



