xv, a 



Perkins: Rancidity of Coconut Oil 



465 



rowed from Ritsert, 9 is obviously at variance with Walker's 

 conclusions. 



Lewkowitsch also points out that the chemical nature of the 

 final products of the rancidity process is still an open question. 

 This phase of the subject is beyond the scope of the present 

 investigation. 



The purposes of this article are to present evidence as to 

 the relative effect of various factors in the development of 

 rancidity in edible coconut oil, and to point out wherein this 

 evidence leads to a confirmation, modification, or extension of 

 the above-quoted conceptions of rancidity. The rancidity fac- 

 tors studied were: initial acidity, air, light, moisture, enzymes, 

 and nonfatty material. A discussion of these in detail will be 

 taken up following a description of the storage experiments. 



STORAGE EXPERIMENTS 



Samples for the investigation were prepared by Mr. H. 0. 

 Parker, of the Bureau of Science, as follows: 



Fresh coconut meat was dried in the laboratory and ex- 

 pressed. About 1 liter of practically colorless but cloudy oil 

 was thus obtained, having an acidity of 0.37 per cent. This 

 will be designated as oil A. 



Oil A was divided into six parts, which were treated as de- 

 scribed in Table I. 



Table I.— Treatment of oil before storage. 



Designation. 



Treatment. 



Rancidity factors. 



1 





Fat-soluble enzymes. 



2 '.„. 



3 



4 









No. 1 sterilized 10 hours at 105° C .. .. 



(microorganisms"), moisture, non- 

 fatty material. 



None of the above. 



Moisture. 



Moisture and nonfatty material. 



5 





6. 









By enzymes and microorganisms are meant only such enzymes 

 and microorganisms as may be present in oil obtained as above 

 described. The term nonfatty material refers to the substances 

 — largely protein and carbohydrate — that, together with mois- 

 ture, give the cloudy appearance to freshly expressed oil, and 

 which are removed by filtration through fuller's earth. 



9 Ritsert, Untersuchung tlber d. Ranzigwerden d. Fette, Inaug. Dissert. 

 Berlin (1890). 



