46 



BULLETIN 448^ U. S. DEPARTMENT OF AGEICULTURE. 



Table 3. — Behavior of colors when treated with reducing agents followed by oxidizing 



agents. 



[Numbers denoting permitted dyes are in boldfaced type; natural colors are in italics. Dyes common in 

 foods are starred, three stars indicating those most often found. Statements apply in general to 0.01 per 

 cent solutions.] 



No. 



Coloring 

 matter. 



With sodium hydrosulphite. 



Coloring 

 matter. 



Reduction product with air or potas- 

 sium persulphate. 



1 



*462 



Almost decolorized. 



*462 



Color restored. 



2 



434 



Almost decolorized. 



434 



Color partially restored. 



3 



435 



Almost decolorized. 



435 



Color partially restored. 



4 



*436 



Becomes paler very slowly. 



*436 





5 



439 



Paler, slowly. 



439 



Color restored. 



6 



491 



Almost decolorized. 



491 



Some color returns. 



7 



440 



Decolorized. 



440 



Color restored. 



8 



**602 



Pale olive. 



**602 



Color restored. 



9 



**108 



Decolorized. 



**108 



Remains colorless or nearly so. 



10 



***8 



Decolorized. 



:!=i=K8 



Remains colorless or nearly so. 



11 



9 



Decolorized. 



9 



Remains colorless or nearly so. 



12 



**89 



Decolorized. 



**89 



Remains colorless or nearly so. 



13 



692 



Decolorized. 



692 



Color restored. 



14 



399 



Not decolorized. 



399 





15 



***10G 



Decolorized. 



*=f=*106 



Remains colorless or nearly so. 



16 



107 



Decolorized. 



107 



Remains colorless or nearly so. 



17 



94 



Decolorized. 



84 



Remains colorless or nearly so. 



18 



*398 



Decolorized. 



*398 



Remains colorless or nearly so. 



19 



605 



Pale orange. 



605 



Color restored. 



20 



604 



Pale orange. 



604 



Color restored. 



21 



198 



Decolorized. 



198 



Remains colorless or nearly so. 



22 



***14 



Decolorized. 



*=)=!:14 



Remains colorless or nearly so. 



23 



21 



Decolorized rather slowly. 



21 



Remains colorless or pale brownish. 



24 



318 



Bluer; then decolorized. 



318 



Remains colorless or nearly so. 



2.5 



20 



Decolorized. 



20 



Remains colorless or nearly so. 



26 



93 



Decolorized. 



93 



Remains colorless or nearly so. 



27 



***480 



Much paler. 



M:**4g0 



Color restored. 



28 



*53 



Decolorized. 



*53 



Remains colorless or nearly so. 



29 



*55 



Decolorized. 



*55 



Remains colorless or nearly so. 



30 



105 



Decolorized. 



105 



Remains colorless or nearly so. 



31 



4 



Decolorized. 



4 



Remains colorless or nearly so. 



32 



***706 



Not decolorized. 



***706 





33 



56 



Decolorized. 



56 



Remains colorless or nearly so. 



34 



*62 



Decolorized. 



*62 



Remains colorless or nearly so. 



35 



**64 



Decolorized. 



**64 



Remains colorless or nearly so. 



36 



*65 



Decolorized. 



*65 



Remains colorless or nearly so. 



37 



**103 



Decolorized. 



**103 



Remains colorless or nearly so. 



38 



139 



Decolorized. 



139 



Remains colorless or nearly so. 



39 



164 



Decolorized. 



164 



Remaiiis colorless or nearly so. 



40 



**667 



Not changed. 



**667 





41 



*169 



Bluer; then decolorized. 



*169 



Remains colorless or nearly so. 



42 



163 



Decolorized. 



163 



Remains colorless or nearly so. 



43 



170 



Bluer; then decolorized. 



170 



Remains colorless or nearly so. 



44 



84 



Decolorized. 



84 



Remains colorless or nearly so. 



45 



146 



Bluer; then decolorized. 



■ 146 



Remains colorless or nearly so. 



46 



287 



Slowly decolorized. 



287 



Remains colorless or nearly so. 



47 



78 



Slowlj^ decolorized. 



78 



Remains colorless or nearly so. 



48 



***710 



Decolorized, nearly. 



^.=^710 



Color restored. 



49 



*546 



Not changed. 



*546 





50 



1 



Decolorized. 



1 



Not restored. 



51 



507 



Not changed. 



507 





52 



328 



Decolorized. 



328 



Remains colorless or nearly so. 



53 



606 



Pale yellow. 



606 



Color restored. 



54 



154 



Bluer; then decolorized. 



154 



Remains colorless or nearly so. 



55 



85 



Decolorized. 



85 



Remains colorless or nearly so. 



56 



**13 



Decolorized. 



**13 



Remains colorless or nearly so. 



57 



***86 



Decolorized. 



***86 



Remains colorless or nearly so. 



58 



97 



Decolorized. 



97 



Remains colorless or nearly so. 



59 



54 



Decolorized. 



54 



Remains colorless or nearly so. 



60 



329 



Decolorized. 



329 



Remains coIorJe-ss or nearly so. 



61 



139 



Decolorized. 



139 



Remains colorless or nearly so. 



62 



157 



Decolorized. 



157 



Remains colorless or nearly so. 



63 



*95 



Decolorized. 



*95 



Colorless or slightly yellow. 



64 



88 



Decolorized. 



88 



Colorless or slightly yellow. 



65 



*92 



Decolorized. 



*92 



Remains colorless or nearly so. 



66 



101 



Decolorized. 



101 



Remains colorless or nearly so. 



67 



102 



Decolorized. 



102 



Remains colorless or nearly so. 



68 



483 



Decolorized. 



483 



Color restored. 



69 



*510 



Much palei'. 



*510 



Color restored. 



70 



26 



Decolorized. 



26 



Remains colorless or nearly so. 



71 



220 



Decolorized. 



220 



Remains colorless or nearly so. 



72 



269 



Decolorized. 



269 



Remains colorless or nearly so. 



73 



512 



Much paler (with excess). 



512 



Color restored. 



74 



515 



Much paler (with excess). 



615 



Color restored. 



75 



516 



Much paler (with excess). 



516 



Color restored. 



