UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 717 ,,, 



j/^. __, _ __ ^ ^_ _ -^ 



Contribution from the States Relations Service 

 A. C. TRUE, Director 



Washington, D. C. 



PROFESSIONAL PAPER 



September 25, 1918 



DIGESTIBILITY OF PROTEIN SUPPLIED BY SOY- 

 BEAN AND PEANUT PRESS-CAKE FLOURS.' 



By Arthur D. Holmes, Specialist in Charge of Digestion Experiments, Office of Home 



Economics. 



CONTENTS. 



Introduction 1 



Investigations of digestibility of common 

 legimies 2 



Source and available supply of soy-bean and 

 peanut press cakes 3 



Factors considered in determining food 

 value of a protein 4 



The amino acids supplied by soy-bean and 

 peanut proteins as compared ■with those 

 supplied by common cereal proteins 5 



Biologic value of soy-bean and peanut pro- 

 teins as compared with that of common 

 cereal proteins 8 



Digestibility of soy-bean and peanut pro- 

 teins 12 



Preparation of soy-bean and peanut press- 

 cake flours : 12 



The subj ects of the digestion experiments 14 



Preparation of experimental diets 14 



Details of the experiments 15 



The digestibility of protein supplied by soy- 

 bean press-cake flotu' 16 



The digestibility of protein supplied by pea- 

 nut press-cake flovu- 19 



Experiments with flour made from roasted 



peanuts 20 



Experiments with floin- made from raw pea- 

 nuts 22 



Summary of all experiments with peanut 



flours 23 



General conclusions regarding the value of 

 soy bean and peanut flours as food 25 



INTRODUCTION. 



It has long been recognized that in order to maintain the well- 

 being of an individual, or in fact to maintain the normal body proc- 

 esses, proteins of sufficient quantity and quahty are absolutely 

 essential. The proteins normally occurring in the human dietary 

 are of a quite varied natm-e and are derived from both the animal 

 and vegetable kingdoms. Those foods which contain the largest 

 proportion of protein and are ordinarily referred to as protein-rich 

 foods are obtained largely from the animal kingdom and include 

 such food materials as meats, eggs, and milk. 



1 Prepared imder the direction of C. F. Langworthy, Chief, Office of Home Economics. 

 Note.— This bulletin records studies of the digestibOity of protein supplied by soy-bean and peanut 

 press-cake flours. It is primarily of interest to students and investigators Of food problems. 

 64347°— IS-BuU. 717 1 



