4 BULLETIN 1390, U. S. DEPARTMENT OF AGRICULTURE 
a AMARANTH 
Amaranth (CyH,,N20i0S3;Na3), a monazo dye, is made by diazotiz- 
ing naphthionic acid and coupling the product with “R” acid 
(2,31). Very pure naphthionic acid is easily obtainable, and no 
difficulty traceable to this intermediate has been encountered. It is 
most important, however, that the “R” acid used be practically free 
from the isomeric “G” acid and from the lower sulphonated Schaeffer’s 
acid. These couple with naphthionic acid to produce new coccine 
and fast red I, respectively, which are objectionable in food colors. 
Amaranth is very soluble in water, but is readily precipitated from 
its water solution by salting out with sodium chloride. For batches 
intended for certification creat care and experience are needed in this 
operation; otherwise too much salt may be occluded with the dye, 
necessitating the reworking of the batch to bring the percentage salt 
content within the limits specified. 
Amaranth is a reddish-brown powder, which dissolves in water to 
form a magenta-red solution. It is sparingly soluble in alcohol. 
When hydrochloric acid is added to an aqueous solution the color is 
unchanged. The addition of sodium hydroxide to the solution 
intensifies the color. In concentrated sulphuric acid it forms a violet 
solution, which changes through a bluish-violet to a magenta-red on 
dilution with water. 
In 1878 the following patents for the preparation of amaranth 
were issued: German patents 3,229 (56) and 5,411 (4); British patents 
786 (4) and 1,715 (46); French patents 123, 148 (4) and 124 811 (56); 
and United States patent 204,799 (4). 
The analytical data re uired in foundation and supplemental 
affidavits (70), as well as the purity specifications to ettige the dye 
must conform and the methods used in analyzing the dye, are listed 
in Table 2 
TABLE 2.—Specifications for amaranth 
Maximum 
tolerance Minimum Method of 
(ratio to pure} tolerance analysis 
coal-tar dye) 
Component 
Per cent Per cent Page 
IWMioistiite s <5 Se a Oe eae a ee 5. Oe AGE Les ee 
Insoluble matter 
Oba sb! 6 ee ae hee eles Abe wa Mt a Be 15 
Nonvolatile-2. Was oh. eB al 3 es ee ead © Die © oy eee’ eee ws 15 
Soditim: chlorides) 32°52... ea a ee eae A, \Qieeg? fee eee 45546; 
Sodiunmsulphateth tia. 2 )..6. ces ha ee 5 Fe eens cee Bs sD ee eee cee ES F 
Bulpiatedrash : (U5 bec 2. ae) eh ae eet Lyin. » ams] ten = oe RS 18. 
Sodium’ tn Colors= 205. tae et ee ee ee Theoretieal.-|_.--<---2—— 18. 
Een yayInebaiss | Pde. es ee eee one: '[2=-4-. Se" 19. 
Gal Cunme. See ee eh eh Le Pah ee DirSee ie. = rete Lieeetel 19 
Mister OSHS ty he See Sk a ee SS ae ae ear ee oes oe 19 
ASIMIN Hn eee bes Ll ee ae ee ee Ape crate Leer ee 0 19. 
1 Eyes 0 se Se AD Jy Ope SEN NOP ay eer ae 2 Ot aerate oe esl ne FXG VET AS ctl on A Dee Sopra 
ATSOMICAS Ass Opks. tach. te a ee ee a ese 00014 a2. -t eS 21, 22, 23. 
Ether extractives: 
INGUrALR -o = S00 Pa Ree ee ee ee ee ¢) en ree ee 23. 
WASNT 3 AUS tae 8 oe te A 8 ae ol ee ee (L) on. ile ds ee P33 
pACiG MUR Se Ou eS Se eo oe 2. oe OR ee (Dye ot ee ae 24. 
fa) 2) Ma 2 sel 9 SS 6 ee Sa PLSD EPC en ey Se bead eB A LS Fe eee 5 oe 24. 
Benno in Colors st) saat + shen « he Se ee eee Theoreticali-|s22s53-—*. 24, 
BD OLGR Cl oP ae ee ee ae ee A ee 13. Nuke 
Pore coal-tar: dye 1240S Bt VET en 2 as eee BOL ER ae ee 82 | 26 
Lower sulphonated dyes as fast red E__..________-_-_----____- \ 40 { peepee ie tee 28. 
isomeric dyes as new eoccine: =.7 2. eee SS ; 
1 Although no limit is here defined, a statement of the percentage found by analysis must be incorporatea 
in the foundation and supplemental affidavits (70 
15.0 14, 
Total , ; 
5 17 
(1) 
N 
: 19. 
2 
py 
