er ye 
4 BULLETIN 1159, U. S. DEPARTMENT OF AGRICULTURE. 
of the flesh had fully developed, and the solids-acid ratio was greater | 
than 8 to 1. The taste was still somewhat sour. By October 140 
the fruit was entirely satisfactory to the taste, while only a small 
amount of yellow showed about the calyx. By October 27 only 20 
per cent of yellow color had developed. On November 8 the fruit 
yas practically full colored. “4 
Studies of many tests made in the field seem to show that shortly § 
after full orange color develops the acidity of the fruit tends to § 
decrease to such an extent that it becomes insipid in flavor, while 
the pulp portion of the fruit separates from the peel. A high ratio — 
of soluble solids to acid does not apparently indicate in all cases*a 
high flavor. The soluble solids were seldom above 10.5 per cent, 
while the acid late in the ‘fall frequently drops to 0.5 per cent, or 
even. lower, thus giving a high ratio. Two sets of samples which 
yy ees 
Lt li eat 
were taken periodically from two different locations in a certain 
grove show how the acidity decyeases toward the end of the season, | 
rendering the fruit less sprightly in flavor than it was a month or | 
six weeks earlier. Fruit from this grove was not fully colored on the | 
tree until about November 12. Table 3 shows the results of four § 
solids-acid tests made between September 16 and November 15. — 
While the acid in fruit from location A decreased from 1 per cent j 
to 0.49 per cent and in location B from 1.1 per cent to 0.45 per 
cent, the soluble solids in A increased from 7.6 per cent to 10.3 per — 
cent and in B from 7.6 per cent to 9 per cent. The ratio of soluble — 
¥ 
ers 
solids to acid therefore increased in location A from 7.6 to 21 and in — 
loeation B from 6.9 to 20. 
TAsie 3.—Determinations of solids, acidity, and color of oranges from a single 
grove picked at intervals from September 16 to November 15. 
ye Solids- 
- F Citric Soluble : Yellow 
Date. Location.| acid. solids. aed color. 
atio. 
Per cent. | Per cent. - | Percent. 4 
seprembernl6:. (. -2se2 Ss. - So oe ee eee eee ae ee A 1.00 7.6 7.6 0” 
B 1.10 7.6 6.9 og 
September.29- 5: 2.2 See ees SE eee A - 88 do 8.5 10g 
B -90 8.5 9.5 be 
Metopervo. 02) aS an Ds ae es eee, oe A 52 8.5 16.3 20 
B 5d 8.5 15.7 50 
A 49 10.3 21.0 90 
IN OVENTDEI Ds oye wee bee eft ee Ke eee anes B 45 9.0 20. 0 100 
| C 34 9.0 26. 5 100 } 
It is evident then that the fruit will in practically all cases pass i 
the test prescribed for oranges in interstate commerce by food in- 1 
spection decision 182 of the United States Department of Agricul- © 
ture, which provides that the “juice of the mature fruit contains not 
less than eight parts of soluble solids to each part of acid calculated 
as citric acid without water of crystallization,” which is usually some — 
time before it attains full color.on the tree. 
It is also apparent from the results of the experiments just de- | 
scribed that the color of the skin of an orange is no criterion of its — 
physiological maturity nor of its attractiveness and desirability as 
