254 IV. DIGESTION OF LIPIDS OTHER THAN FATS 



In the case of the dog tests, stearyl citrate was found to be only partially 

 hydrolyzed, as determined by analysis of the feces. It was found that 

 67.6% of the stearyl alcohol was present as the ester in the feces, while 

 32.4% occurred as the free alcohol. The method employed in calculating 

 the proportion of free and combined stearyl alcohol from the analytical 

 values is illustrated in Table 2. 



Table 2 



Determination of the Proportion op Stearyl Citrate and Stearyl Alcohol 

 Excreted in the Feces op Dogs after the Administration of Stearyl Citrate" 



Category Dog 9 Dog 10 



Stearyl alcohol excreted: 



(a) Non-saponifiable fraction (N.S.F.), tolal, mg 258 219 



(b) N.S.F., control value, mg 33 33 



(c) Stearyl alcohol, total, mg. (a - b) 225 186 



Citric acid excreted : 



(d) As free acid (before hydrolysis), mg 



(e) Combined (after hydrolysis), mg 46 49 



Distribution of stearyl alcohol: 



(/) Total, mg. (c) 225 186 



(g) Combined, mg. (e X 540 (M.W. stearyl citrate)/ 



192 (M.W. citric acid)) 129 138 



(h) Free, mg. (/ - </) 96 48 



Calculation of stearyl citrate hydrolyzed: 



(0 Total stearyl citrate, mg. (c X (696/540)) 290 240 



0") Unhydrolyzed, mg. (e X (696/192)) 166 178 



(k) Hydrolyzed, mg. (i - j) 124 62 



(I) Hydrolyzed, % (Jc/i X 100) 42.8 25.8 



Calculation of stearyl alcohol and stearyl citrate in 

 feces: 



(to) N.S.F., total g 14.7 16.1 



(n) N.S.F., corrected, g. 6 12.3 13.2 



(o) Stearvl alcohol in feces, g. (n X I) 5.3 3.4 



(p) Stearyl citrate in feces, g. (n X (160 - I) X 



696/540) 9.1 12 6 



(?) Total, g. (o + p) 14.4 16.0 



a Adapted from C. E. Calbert, S. M. Greenberg, G. Krvder, and H. J. Deuel, Jr., Food 

 Research, 16, 294-305 (1951). 



6 Control N.S.F. (estimated as 17.2% of dried feces) subtracted from m. 



(2) Waxes Containing Cyclic Alcohols 



Cholesterol and other sterol esters are the chief wax-like products which 

 contain a cyclic alcohol. These esters are hydrolyzed with more dif- 

 ficulty than are the neutral fats. In order to bring about hydrolysis in 

 the test tube, special means must be employed to rupture the ester link- 

 age, such as long continued heating or the use of sodium ethylate in ethereal 



