ABSORPTION AND DIGESTIBILITY OF WAXES 253 



gastrointestinal tract, or was converted to another substance. There is 

 considerable experimental proof that the latter explanation is the more 

 probable one. 



The occurrence of cetyl palmitate to the extent of 90% of the total 

 composition of spermaceti and to a considerable extent in sperm oil 26 is in 

 sharp contrast to its absence from other animal fats. It suggests that 

 the sperm whale (Physeter macrocephalus Linn6) and the bottlenose whale 

 (Balaena rostrata), from which spermaceti is obtained, may be able to 

 synthesize cetyl palmitate in situ, since the wax is not widely distributed 

 in marine species other than cetaceans. 



c. Distearyl Citrate. Calbert et al. 27 studied the digestibility of a wax- 

 like ester, distearyl citrate. This ester, which acts as an anti-flavor-rever- 

 sion agent toward soybean oil, is an oil-soluble wax which has been shown to 

 be completely innocuous when fed to rats, rabbits, and dogs. 28 



H 2 CCOOH 



HOCCO-OCH 2 -(CH 2 ) 16 -CH 3 



•CO-OCH 2 (CH 2 ), 6 CH 3 

 Distearyl citrate 



H 2 C-< 



When distearyl citrate was fed to rats in amounts of 2.5 or 10% of the 

 diet, it was digested to the extent of only 5.7 or 19.3%,, respectively. 

 Furthermore, a concomitant decrease in fat utilization obtained; the 

 coefficients of digestibility reported for the fats were 77.1 and 71.6 when 

 the wax was added to the diet to the extent of 2.5 or 10%, respectively. 

 On the other hand, when stearyl citrate comprised only 0.13% of the diet, 

 the figure for fat digested was 94.1%, as contrasted with a control value 

 of 95.2%. 27 



Moreover, when distearyl citrate was fed to dogs at a level of 3%, it 

 was also digested to the extent of only 52.2%, on an average. However, 

 under these circumstances, no appreciable interference in fat absorption 

 obtained, since the mean coefficient of digestibility of the fats was 94.5. 27 

 On the other hand, isopropyl citrate ester (chiefly the mono-ester) was 

 completely utilized by the rat and dog, and no trace of it could be demon- 

 strated in the feces; doses as high as 10% were administered to rats, 

 while the ester preparation made up only 0.06% of the diet fed the dogs. 



26 A. H. Warth, The Chemistry and Technology of Waxes, Reinhold, New York, 1947. 



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

 294-305(1951). 



28 H. J. Deuel, Jr., S. M. Greenberg, C. E. Calbert, R. Baker, and H. R. Fisher, Food 

 Research, 16, 258-280 (1951). 



