THE RANCIDITY OF PHILIPPINE COCONUT OIL 



By Granville A. Perkins 



Chemist, Bureau of Science 



In a paper entitled The keeping qualities and the causes of 

 rancidity in coconut oil, H. S. Walker l called attention to the 

 ravages of mold on moist copra and impure coconut oil, pointing 

 out that - 



The action of light and air on coconut oil is of relatively little importance 

 in comparison with the great changes produced by mold growth, and it 

 can be prevented in a large degree by keeping oil receptacles as nearly 

 full as possible, so as to reduce the amount of surface exposed. 



He further indicts the molds as follows : : 



• * it seems highly probable that these molds produce a slowly 



acting enzyme, soluble in oil, which continues its hydrolytic action even 

 after the organisms themselves are dead. This would account for the 

 steady increase in free acid of some commercial oils which are perfectly 

 clear and free from impurities and which have been proven to contain 

 no living bacteria or molds. * * * 



In a later paper, The production of free acid in commer- 

 cial coconut oil on long standing, Walker + gives the following 

 conclusions : 



The deterioration of a freshly prepared commercial coconut oil is 

 produced by at least three entirely independent processes and may be 

 divided into two distinct periods of time. 



The first, rapid splitting up of the fat, beginning immediately after 

 its expression from copra and continuing for several months up to a year 

 or more according to the nutrive [nutritive] matter present, is occasioned 

 by molds which are either pressed out with the oil together with sufficient 

 sugars and albuminoids for their growth, or, in the case of hot pressed 

 oils, enter the freshly prepared oil from the air. This action continues 

 as long as sufficient nutritive material for mold growth remains in the oil. 

 It may be completely checked by filtration, preferable [preferably] after 

 heating to 100° C. more thoroughly to coagulate albuminoids and to destroy 

 any enzymes already secreted by the molds. 



Toward the end of this first period, oxidation by the air sets in and 



1 Philip. Journ. Sci. 1 (1906) 117-172. 



s Op. cit. 142. 



a Op. cit. 135. 



1 Philip. Journ. Sci. § A 3 (1908) 126-135. 



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