THE RANCIDITY OF PHILIPPINE COCONUT OIL 
By Granville A. Perkins 
Chemist, Bureau of Science 
Iii a paper entitled The keeping qualities and the causes of 
rancidity in coconut oil, H. S. Walker 1 called attention to the 
ravages of mold on moist copra and impure coconut oil, pointing 
out that 2 
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 : 3 
* * * 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 contairt 
no living bacteria or molds. * * * 
In a later paper, The production of free acid in commer- 
cial coconut oil on long standing, Walker 4 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. 
■ Op. cit. 142. 
3 Op. cit. 135. 
4 Philip. Journ. Sci. § A 3 (1908) 126-135. 
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