COLORING SATSUMA ORANGES IN ALABAMA, 5 
: 
an article of diet. If the fruit is allowed to remain on the tree until 
it attains a full golden yellow color it is liable to be somewhat insipid 
) and not at all as desirable for eating as it would have been earlier 
- in the season. 
EXPERIMENTAL WORK IN COLORING SATSUMA ORANGES. 
. EXPERIMENTS IN 1919. 
The experiments in coloring Satsuma oranges described in this 
bulletin were begun in 1919 at Silverhill, Ala., and continued in 1920 
and 1921. The first efforts were entirely unsuccessful because the 
stoves were not properly adjusted to give off the necessary gas. Both 
kerosene portable heaters and ordinary cookstoves of the blue-flame 
- cotton-wick type were used. These were operated in the ordinary 
way, allowing complete combustion with no perceptible offensive 
fumes. The experimental house in which this work was carried on 
comprised three rooms 6 by 12 feet. with 6-inch flooring laid with 
half-inch open spaces between. The stoves were located below each 
room in pits which communicated with the outside. For the first 
experiments, because of the comparatively small quantities of fruit 
used, a false ceiling was erected in each room about 3 feet above the 
floor. The temperature was maintained at about 90° F., with a 
humidity between 60 and 85 per cent. Kerosene and a so-called “* gas 
oil,” a low-grade distillate, were used singly and combined in various 
proportions in the stoves, but the green color of the fruit remained 
practically unchanged even after as long a period as 10 days. When 
kerosene alone was burned a slight color change was noted, but it 
developed so slowly that the fruit began to break down before any 
considerable change took place. It became quite evident that Sat- 
suma oranges could not be satisfactorily colored by operating kero- 
sene stoves in the ordinary way. ‘This is in accord with the results 
obtained in California by Sievers and True with lemons. They 
found that “ heat and humidity are of minor importance in coloring 
) lemons and that the pungent gaseous combustion products given off 
_ by the oil stoves used produced the desired effect.” 
In connection with the preliminary coloring experiments it was 
observed that after five or six days in the coloring rooms the oranges 
were much improved in flavor. This change in flavor was accom- 
panied by an increase in the solids-acid ratio; that is, the acid de- 
creased while the soluble solids increased, thus making a sweeter 
fruit. This is shown by the analyses given in Table 4. 
TABLE 4.—Increase in solids-acid ratio in four lots of Satsuma oranges 
during coloring in 1919. 
-..-, | Solu- | Solids- | Asa | Solu- | Solids- 
Lot. Color stage. eee ble | acid Lot. Color stage. Soe ble | acid 
* | solids.| ratio. “eS | solids. | ratio. 
EP Chel aces | | Prchs || Pack 
Lot A | Before coloring..... 1.25 |. 8.60 6.9 || Lot C_| Before coloring... .¥ 0.88 | 7.52 8.5 
7 After coloring.-..... 1.15 | 9.82 8.5 After celoring..... -82|] 8.81 10.8 
Lot B | Before coloring..... 1.25] 860 6.9 |} Lot D | Before coloring...-..: y -90} 853 9.5 
After coloring. ..... 1.20 | 9.82 8. 2 After coloring...... -81 | S81 10.9 
| 
sare 
| 
| 
