STABILITY OF OLIVE OIL^ 



By E. B. Holland, Associate Chemist, and J. C. Reed and J. P. Buckley, Jr., 

 Assistant Chemists,- Masmchusetts Agricultural Experiment Station 



INTRODUCTION 



Some years ago one of the writers reported the results of an experi- 

 ment to determine the efifect {4f of air, light, and moisture at room 

 temperature on butter fat. The test was planned to show the action 

 of the three agents, singly and in combination, and was continued for 

 a year and a half. The experiment furnished considerable information 

 relative to the changes that take place in such materials, but proved 

 faulty in that a fat, solid and opaque at ordinary temperature, was a 

 poor medium for measuring such changes, which evidently were not 

 uniform throughout the mass, but greatest at the surface; furthermore, 

 the conditions surrounding the fat were not under satisfactory control. 



Conceding the limitations of the previous experiment, but recognizing 

 the economic value as well as scientific interest of such investigations, 

 the writers deemed it advisable to conduct another series of tests, under 

 more definite conditions. For this purpose all oils procurable in quan- 

 tity at a reasonable price were carefully considered. Olive oil was finally 

 selected for the reason that it is a well-known edible product of fair 

 keeping properties and of the composition desired. 



THE OIL EMPLOYED 



A few letters of inquiry to Federal and Experiment Station officials 

 elicited the information that pure olive oil, both foreign and domestic, 

 was readily obtainable. As an American oil could be procured directly 

 from the pressers in a comparatively short time, with details of produc- 

 tion and treatment, an order was placed, specifying an absolutely pure 

 product that had not been bleached, sterilized, or refined in any way 

 except as to filtration and having a low content of free fatty acids. 



A 5-gallon can of California olive oil was received on February 25, 

 1 910. The manufacturer stated that the oil was cold-pressed from an 

 average run of hand-picked, washed, and ground ripe California-grown 

 olives of the season of 1908. After extraction, the oil was pumped into 

 settling tanks and from there to storage tanks, whence it was filtered 

 four to six times through French filter paper in a special press and was 

 not put on the market until it was at least a year old. 



1 From the Department of Chemistry, Massachusetts Agricultural Experiment Station. Printed with 

 the permission of the Director of the Station. 



2 Mr. Reed was associated with the senior writer in the earlier stages of the work and Mr. Buckley in 

 the later. 



' Reference is made by number (italic) to "Literature cited," p. 366. 



Journal of Agricultural Research, Vol. XIII, No. 7 



Washington, D. C. May 13, 1918 



nj (353) Key No. Mass.-5 



