UNITED STATES DEPARTMENT OF AGRICULTURE 
s^&'iF-ru 
BULLETIN No. 781 
Contribution from the States Relations Service 
A. C. TRUE, Director 
Washington, D. C. 
PROFESSIONAL PAPER 
May 31, 1919 
DIGESTIBILITY OF SOME BY-PRODUCT OILS. 
By Arthur D. Holmes, Specialist in Charge of Digestion Experiments, 
Office of Home Economics. 
CONTENTS. 
Page. 
Introduction 1 
Previous investigations 1 
Possible recovery and use of by- 
product oils 2 
Digestion experiments with men 3 
Apricot-kernel oil 4 
Page. 
Cherry-kernel oil 6 
Melon-seed oil 8 
Peach-kernel oil 10 
Pumpkin-seed oil 12 
Tomato-seed oil 14 
Discussion 15 
INTRODUCTION. 
In planning the experiments to determine the digestibility of 
edible fats it was early recognized that in order to be of greatest 
value the experiments with the different fats should be conducted 
under as nearly as possible identical conditions. Accordingly, the 
same experimental methods have been used throughout a series with 
40 or more edible fats to which the present study is the most recent 
contribution. These methods were quite fully discussed in the 
initial report of this series. 2 As a result of this uniformity of method, 
the value reported for the digestibility of any individual fat dis- 
cussed is directly comparable with the figures obtained for the 
others. 
PREVIOUS INVESTIGATIONS. 
Papers have appeared from time to time, reporting the digesti- 
bility of such animal fats 3 as lard ; beef fat ; mutton fat (kidney fat) ; 
butter ; cream ; chicken, goose, brisket, egg-yolk, and fish fats ; goat's 
1 Prepared under the direction of C. F. Langworthy, Chief, Office of Home Economics. 
2 TL S. Dept. Agr. Bui. 310 (1915). 
3 U. S. Dept. Agr. Buls. 310 (1915), 507 (1917). 
Note. — This bulletin records studies of the digestibility of apricot-kernel oil, cherry- 
kernel oil, melon-seed oil, peach-kernel oil, pumpkin-seed oil, and tomato-seed oil. It is 
primarily of interest to students and investigators of food problems. 
106003°— .Bull. 781—19 1 
