DETECTION OF FOREIGN COLORING MATTER. 



27 



Table 1. — Coloring matter of fruits. 



Fruit. 



Coloration of acid aolu- Coloration of ammoniacal 

 tion.a solution. 



Addition of a drop of 



Juice. 



^■"eSS.'^-'l '"'-■ 



Amyl-alcohol 

 extract. 



H2SO4 to dyed fabric. 





Red 



Red 



Red 



Red 



Red 



Red 



White.... 

 Dark red . 

 Yellow . . . 

 Yellow... 

 Yellow . 



1 



Yellow Green 



Uncolored 



Uncolored 



Uncolored 



Uncolored 



Uncolored 



Uncolored 



Uncolored 



Uncolored 



Yellow red . . . 

 Yellow red . . . 

 Yellow red . . . 

 Yellow red . . . 

 Yellow red . . . 

 Yellow red . . . 



Yellow. 



Ripe cherries 



Uncolored . . 



Rose 



Red 



Red 



Uncolored . . 

 Uncolored . . 

 Red 



Uncolored . . 

 Uncolored . . 



TTnnnlnred 



Green 



Green 



Green 



Green 



Green 



Brown 



Deep green . 



Brown 



Brown 



Brown 



Yellow. 



Early strawberries 



Ripe strawberries 



Raspberries 



Rose. 



Rose (tints silk a rose 

 red.) 







White currants 



Black currants 



Peaches 



Pears 



Quinces 



Tints silk rose. 

 Uncolored. 









Apricots 



Yellow - . . 

 Yellow . . . 



Uncolored Brown 





Green gage plums 



Uncolored . . 



Brown 





'Acidity of the juice. 



Table 2. — Coloring rnaiter of fruits. 



Fruit. 



Color with 

 NH4OH. 



Ether ex- 

 tract from 



acid 

 solution. 



Amyl-alcohol 

 extract from 

 acid solution. 



Dyeing tests on the juice. 



Strawberry 



Purple 



None 



Deep red 



Color washed out. 



Red raspberry 



Purple 



None 



Deep red 



All color does not wash out, but does 

 not dye in the second acid bath. 



Blackberry 



Blue-purple . . 



None 



Very deep red . 



Dyes purplish red in acid solution, 

 but does not dye in the second acid 

 bath. 



Cherry 



Purple 



None 



Red 



Dyes purplish red in acid solution, 

 but does not dye in the second acid 



















bath. 



Blackberry 



Blue-purple .. 



None 



Red 



Dyes purplish red in acid solution, 

 but does not dye in the second acid 



















bath. 



Wild dewberry 



Blue-purple .. 



None 



Red 



Dyes purplish red in acid solution, 

 but does not dye in the second acid 



















bath. 



Currant 



Blue-purple . . 



None 



Red 



Dyes purplish red in acid solution, 

 but does not dye in the second acid 

















bath. 



It will be seen from these two tables that amyl alcohol, as a rule, 

 extracts fruit coloring matter from acid solution, while ether does 

 not. Neither amyl alcohol nor ether extracted any color from alka- 

 line solution of the fruit juices. 



