3io 
Study  of  Fruit  and  Vegetable  Colors. 
|  A.m.  . 
July,  1905. 
The  following  results  were  obtained : 
Tests  with  reducing  agents.  The  following  fruit  colors  produce 
no  change  in  zinc  and  hydrochloric  acid  or  in  a  solution  stannous 
chloride  :  Blackberry,  cherry  (black),  cherry  (red),  cranberry,  cur- 
rant, elderberry,  grape,  huckleberry,  plum,  raspberry,  strawberry. 
TESTS  WITH   REDUCING  AGENTS. 
Other  Vegetable  Colors. 
Zinc  and  Hydrochloric  Acid. 
Solution  Stannous  Chloride. 
Annatto 
no  change 
no  change 
Beet  Juice 
slightly  lighter 
no  change 
Brazilwood 
much  lighter 
no  change 
Cochineal 
no  change 
no  change 
Cudbear 
decolorizes 
decolorizes 
Fustic 
decolorizes 
no  change 
Litmus 
decolorizes 
decolorizes 
Logwood 
slightly  lighter 
no  change 
Madder 
no  change 
no  change 
Marigold 
decolorizes 
no  change 
Red  Saunders 
no  change 
no  change 
Safflower 
no  change 
no  change 
Saffron 
decolorizes 
no  change 
Turmeric 
decolorizes 
no  change 
lmercial  Coal  Tar  Colors. 
One 
decolorizes 
decolorizes 
Two 
decolorizes 
decolorizes 
Three 
decolorizes 
decolorizes 
Four 
decolorizes 
decolorizes 
In  glancing  over  the  preceding  table  it  will  be  seen  that  none  of 
the  pure  fruit  colors  are  affected  by  either  of  these  reducing  agents, 
while  some  of  the  other  vegetable  colors  are  either  considerably 
modified  or  completely  destroyed,  and  in  the  cases  of  every  one  of 
the  synthetic  colors  examined  complete  decolorization  took  place, 
although  it  must  be  said  in  explanation  that  there  are  some  non- 
reducible synthetic  colors  in  use  at  the  present  time. 
It  will  also  be  seen  that  of  all  of  the  vegetable  colors  only  cud- 
bear and  litmus  are  affected  by  the  stannous  chloride  solution, 
which  adds  another  factor  to  the  ease  of  their  identification. 
In  view  of  the  fact  that  chlorophyll,  which  is  often  used  as  a 
source  of  commercial  green  colors,  shows  certain  easily  recognizable 
characteristics  when  observed  through  the  spectroscope,  this  method 
of  examination  was  applied  to  every  one  of  the  foregoing  colors 
without  any  distinctive  results  whatever. 
