UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 448 



Contribntion from the Bureau of Chemistry 

 CARL L. ALSBERG, Chief 



Washington, D, C. 



PROFESSIONAL PAPER 



February 15, 1917 



SEPARATION AND IDENTIFICATION OF FOOD 

 COLORING SUBSTANCES 



By 



Wc E. MATHEWSON, Assistant Chemist 



CONTENTS 



Page 



Introduction 1 



General Statements Concerning Re- 

 agents Used in Color Analysis .... 2 

 Preliminary Treatment of Food Products 4 



Separation and Purification of Coloring 



Substances 8 



Identification of Coloring Substances . . 35 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1917 



