369 



OILS AND FATS. 



THE KEEPING QUALITIES AND THE CAUSES OF RANCIDITY IN 



COCONUT OIL. 



(Summary.) 



Soil.— In attempting by means of soil analyses to explain why coconut trees 

 growing near the seashore are more prolific than those planted farther inland, it 

 was observed that— 



(1) Chemically, there is very little difference in soils from the two localities 

 those from inland regions being, if anything, a little more fertile. 



(2) The salt water from the sea has no influence on trees in its vicinity, as 

 only amounts of chlorine so small as to be negligible were found to be present even 

 at the bases of coconut trees which were actually growing on the beach. 



(3) The greater porosity of soils near the sea coupled with the fact that 

 they are, as a rule, practically saturated with water at a distance of only a few 

 feet beneath the surface of the ground, is the principal reason why they are more 

 suitable for trees like the coconut, which require an enormous quantity of water 

 for their growth. 



(4) Although good coconut soils are apparently almost devoid of fertility, 

 yet, taking into account the character of coconut roots and the large area from 

 which each tree draws nourishment, it can be demonstrated that there exists 

 an ample supply of nutriment for their growth. 



The Nut; Age in Reference to Quality.— (1) The variations among indi- 

 vidual nuts is sufficiently great to render exact conclusions from analytical data 

 difficult, but, taking the average of a number of determinations, there appears to be 

 slight increase in the proportion of meat, copra, and oil in nuts which have been stored 

 up to a maximum time of three months after catting. Beyond this period there is a 

 decided decrease in these constituents. Nuts taken from the same tree show 

 somewhat less individual variation. 



(2) Four series of ten nuts each, of varying degrees of ripeness, showed a 

 marked difference in the amount of copra and of oil to be obtainable from 

 them, the percentage of the oil in a green nut being only about one-half of 

 that which it is when the nut is fully ripe. This ripening process continues 

 to some extent, on storage, after cutting. 



(3) Analyses of coconuts from the same locality, but having husks of 

 different colour, prove that the colour of a nut has very little if any influence on its 

 composition. 



(4) The difference between trees near the seashore and those farther inland 

 is solely in the quantity, not in the quality, of nuts which they produce, coconuts 

 from inland regions averaging fully as well as those 1 from the beach. This fact is 

 shown both by analyses and by practical tests on a large scale. 



(6) Coconut oil is generally stated to have a great tendency to become 

 rancid, but all the experiments made in this laboratory show that, when once 

 prepared in a pure state, its keeping qualities are equal if not superior to those of 

 most other vegetable fats and oils. This popular fallacy in regard to coconut oil 

 probably arose from the inability or disinclination on the part of most observers 

 to procure pure samples, as the commercial product unquestionably has a high 

 acid value and a bad odour, and deteriorates with fair rapidity, this change 

 being greater as a rule the greater the initial acidity of the oil. 



