COLORING CITRUS FRUIT IN FLORIDA i 
38 hours, gas from a kerosene stove being applied for the entire 62 
hours. At the end of this time the fruit was approximately 50 per 
cent colored. The temperatures of the air and fruit in this expert- 
ment are shown in Figure 2. 
Comparable lots of fruit were placed in three other coloring 
rooms. The first had a temperature ee from 77° to 84° F., 
or about 80° on the average; the second 75° to 79°, an average of 77°; 
and the third an average of 78°, about the same as the second. After 
the gas had been applied for 36 hours to the first and second rooms, 
the fruit was moved out on the packing-house floor and allowed to 
stand 24 hours longer. At the end of that time it was about 90 per 
cent full color in the first or 80° room and between 80 and 90 per 
cent in the 77° room. The fruit in the 78° room was treated with 
gas for 30 hours; at the end of this time it was about 60 per cent full 
color. 
These experiments are of interest in that they show the importance 
of the proper temperature for coloring the fruit if it is to be done 
rapidly. The experimental work, during the three years it was in 
progress, was supplemented with numerous observations in the color- 
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Fic. 2.—Diagram showing the air and fruit temperatures in the coloring room 
during experiment 3 
ing rooms, showing conclusively that it required from four to five 
days to obtain 100 per cent orange or yellow color on fruit giving 
no indication of yellow when placed in the coloring room. Fruit 
would assume a yellow or orange color more quickly at 70° to 75° F. 
than at lower temperatures; at 80° to 85° oranges would show a dis- 
tinct yellow color after about 36 hours continuous exposure to the 
gas. Grapefruit, under the latter condition, would show a marked 
color in 24 hours. In practice, most fruit when placed in the color- 
ing room is partially yellow, and the time in which it can be made 
to assume the full yellow color is dependent to a considerable extent 
on the proportion of color on the fruit at the beginning. For 
rapidity of operation, then, it is important that the coloring room 
be maintained at temperatur es of 80° to 85° F. Itis also advisable to 
pick only fruit showing at least a tinge of yellow. This is particu- 
larly true for tangerines, which will not assume in the coloring room 
the rich, reddish orange ‘typical of the variety, unless they have be- 
gun to color on the tree. Very good results were obtained with 
tangerines showing 15 to 50 per cent of color by exposing them to 
stove gas at a temperature of 75° to 80° F. with 85 to 90 per cent rela- 
tive humidity for 60 to 72 hours. 
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