UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 666 
Contribution from the Bureau of Chemistry 
CARL L. ALSBERG, Chief 
_ Washington, D. C. PROFESSIONAL PAPER May 9, 1918 
THE EFFECT OF ALKALI TREATMENT ON COCOAS. 
By Evucene BuoomMsere, formerly Assistant Chemist, Buffalo Food and Drug 
Inspection Station. 
CONTENTS. 
Page. Page 
Purpose of the investigation................. 1 | Ashratiosin untreated and treated cocoas... 16 
Description of investigationalsamples....... 3 | Action of various alkalies on cocoas.......... 18 
Analyses of untreated and treated cocoas.... 4" Appearance of the cocoas: -2.2-...-.4....--- 19 
Water-soluble matter in untreated and treated ConclusionSs*em-swer cee tase 4 soa aes 20 
COGS Se Sh co sbdsc. GSB nee ae 9 
Composition of the water-soluble matter in 
% untreated and treated cocoas............--- 14 
PURPOSE OF THE INVESTIGATION. 
N THE PROCESS of the manufacture of cocoa, the cocoa beans 
are roasted, the shells removed, the nibs crushed in a mill, and the 
resultant product placed in a press whereby a part of the cocoa 
butter is removed. The press cake is then ground and sifted to 
form the cocoa of commerce. By the removal of this portion of fat 
_ the color of the cocoa is made considerably hghter. For many years 
it has been the endeavor of manufacturers of cocoa to darken the 
color of the cocoa so that it would more closely resemble chocolate. 
‘This effect has been sought in various ways, but the most prevalent 
‘method is by the addition of alkalies or alkaline carbonates. Am- 
monium carbonate and magnesium carbonate have also been used 
with this end in view. In this article the term “‘alkali treatment’’ 
will be understood to include the treatment of cocoa not only with the 
alkalies or alkaline carbonates, but also with such salts as ammonium 
carbonate and magnesium carbonate. This process is quite generally 
known as the ‘Dutching”’ process, and the cocoas made therefrom 
as “‘Dutched” or ‘“‘Dutch process” cocoas. The name is derived 
from the fact that this method of treating cocoa originated in Holland. 
_ Attempts have been made at various times to develop this en- 
hanced color by means other than the addition of chemicals. Treat- 
ment with steam, under pressure; wetting the cocoa and allowing 
45789°—18—Bull. 666—1 
