142 Rancidity of Palm Kernel and other Feedinr/ Cakes 



even in the presence of excess of water. A further set of experiments was 

 carried out with six other oil-cakes under precisely the same conditions 

 as for palm kernel cake. In each case there was a development of acidity, 

 suggesting that the presence of a lipase is common to all oil-cakes. The 

 amount of acidity produced was lowest in the case of the palm kernel 

 cake. 



In all cases experiments were repeated several times, for the sake of 

 brevity, however, the general result only is given in the table (p. 141). 



Conclusions. 



Palm kernels and palm kernel cake and meal contain a lipase, which 

 in the presence of moisture and warmth acts upon the oil present, 

 liberating fatty acids, of which the volatile members have a strong 

 sweat-like odour, and a very small amount of these acids is sufficient 

 to impart to the cake a peculiar odour. This change does not occur if the 

 cake is kept dry, a condition which is necessary to the preservation of all 

 feeding cakes. 



Freshly prepared palm kernel cake has a characteristic smell which is 

 probably due to a trace of these acids produced during manufacture. 



Palm kernel cake does not decompose more readily than cotton seed, 

 linseed and ground nut cakes, these latter developing more acidity under 

 similar conditions. These cakes differ from palm kernel cake in not 

 yielding volatile fatty acids on decomposition. Palm kernel cake has 

 been kept at the Imperial Institute for eighteen months and was at the 

 end of the time in good fresh condition and showed no increase in acidity. 

 The only precaution taken was to keep the cake dry. 



(Received June '22nd, 1918.) 



