422 



Keeping Qualities of Oil-cakes 



feature is the high initial acidity in the case of the cottonseed cake, 

 due to the fact, subsequently ascertained, that the cottonseed cakes 

 used were made from a not very satisfactory sample of cottonseed 

 from the notoriously bad crop of 1915. This explanation is borne out 

 by the following data obtained from a number of samples of cottonseed 

 cake examined very soon after their manufacture. 



* Described by the crushers as made from the oldest seed of a very jDoor crop. 



The final acidities, as shown in Table I, are all high, even the soya 

 cake, which is the lowest, having an acidity more than three times the 

 initial value. Leaving out of consideration the abnormal case of 

 cottonseed cake the highest final acidity is shown by the coconut cake, 

 which also shows the greatest relative increase, the lowest relative 

 increase being given by linseed cake. If this final free acidity be 

 taken as a measure of the keeping qualities of the cakes then, after 

 soya and linseed cakes, palm kernel cake is the most satisfactory. 

 These results would indicate that the presence of a fat-splitting enzyme 

 is common to all the oil-cakes and cannot be adduced as a specific 

 disadvantage of palm kernel cake. 



It is difficult to say just what practical significance sliould be 

 attributed to this increase in acidity. The presence of appreciable 

 quantities of free fatty acids in a feeding-stuff is commonly regarded 

 as undesirable but, provided the acidity be not so high as to cause 

 actual derangement of the digestive functions, it is at least doubtful 

 whether the nutritive value of the oil is seriously lowered by this libera- 

 tion of the fatty acids present in it. Such direct evidence as is available 

 points at least to this conclusion. Thus in experiments carried out 

 by Munk(7) equally good results were obtained whether mixed fatty 

 acids were fed as such or in the form of their glycerides, the results 

 indicating that the animal body is capable of building up neutral fat 

 from these free acids and depositing them in the body. 



