NUTRITIVE VALUE OF MIXTURES OF PROTEINS FROM 
CORN AND VARIOUS CONCENTRATES ‘ 
By D. BrEESE Jones, Chemist in Charge; A. J. Finks, formerly Associate Biological 
Chemist; and Carl O. Johns, formerly Chemist in Charge, Protein Investigations 
Laboratory, Bureau of Chemistry, United States Department of Agriculture 
INTRODUCTION 
The nutritive value of mixtures of peanut and soy-bean flours as 
supplements to wheat-flour proteins has been shown in previous publi¬ 
cations { 4 , 5) ^ from this laboratory. This paper is a continuation of 
these studies with whole yellow com. In addition to the peanut and 
soy-bean flours as protein supplements to com are also included meal 
made from tomato-seed press cake and coconut meal made by both the 
solvent and expression processes. Data on both the chemical and nutri¬ 
tional studies of the proteins from tomato seed and coconut have already 
been published (j, d, 7, 8 , 9). Each of the concentrates mentioned has 
been found adequate for the normal growth of albino rats as the sole 
source of protein in otherwise complete diets. 
It has been shown by several investigators that whole corn is not 
adequate for normal growth. Feeding experiments with zein, a protein 
which constitutes more than one-half of the total proteins in maize, 
have shown it to be deficient in lysine and tryptophane—amino acids 
which are essential for the growth of animals. Experiments also have 
been recorded which show that when corn proteins are fed at a high 
enough intake level—as, for example, in corn gluten—^normal growth 
can be secured. 
Whole com constitutes a large part of the ration of many animals and 
it is of practical importance to the feeder to know whether the addition 
of small quantities of protein concentrates such as coconut meal, tomato- 
seed, press cake, soy-bean and peanut flour will result in a protein mixture 
which will meet the nutritional requirements for nprmal growth. Our 
experiments with these concentrates show that a mixture of 25 parts 
of tomato-seed press cake, soy-bean flour, or peanut flour with 75 parts 
of com satisfies the protein requirement for the normal growth of white 
rats. In the case of the coconut meal, equal parts were necessary to 
secure the same result. This may not have been due, however, to 
inferiority in the nutritional value of the coconut-meal proteins, but 
rather to the bulky character of the meal caused by its higher content 
of crude fiber. Chemical studies of the proteins of these concentrates 
have shown that they are relatively high in lysine and tryptophane, 
and are therefore well suited to supplement the corn proteins which 
are deficient in these amino acids. 
EXPERIMENTS WITH WHOLE YELLOW CORN MEAL 
Two diets containing 7.2 per cent of protein in which the proteins 
came solely from whole yellow com were used. Diet i contained 16 per 
cent of butter fat. Diet 2 was made up of the same composition, with 
1 Accepted for publication Nov. 24. 1922. 
2 Reference is made by number (italic) to “Literature cited," p. 977-978. 
Journal of Agricultural Research, 
Washington, D. C. 
ads 
(971) 
43325--23 - 7 
Vol. XXIV, No. XI 
June 16, 1923 
Key No. E-21 
