Jan. s, 1924 
Physiological Studies on Apples in Storage 
33 
Table X. —Relative hardness and acidity in Winesap apples after being held 10 days at 
yi. 5 0 F. (22 0 C.) in various concentrations of C 0 2 - a 
Description of test. 
Pressure 
test. 
Acidity— 
cc. N/ioacid 
per 10 gm. 
wet weight. 
Lot No. 
! Per cent 
1 COa. 
Per cent 
Oa. 
0 
ao 
12.37 
6*55 
5 
20 
13*07 
6.41 
3 . 
10 
20 
13*52 
6.22 
4 . 
20 
20 
13.48 
6.36 
5 . 
50 
20 
14.23 
6.27 
6 . 
100 
O 
14.78 
6.14 
0 Removed from 32 0 F. at beginning of test. Pressure test, 15.37 pounds. Acidity, 6.53 cc. N/10 per 10 
gm. of wet tissue when removed from 32 0 F. 
Internal atmospheres were analyzed from 5 apples of each lot at the 
end of the test. Oxygen present in all fruits (except lot No. 6, not 
analyzed) ranged from 6 to 13 per cent, while C 0 2 ranged approximately 
20 per cent above the concentration of the surrounding atmosphere. 
These analyses indicate that there was in all lots an abundance of 0 2 
within the tissue. 
There was a marked relationship between C 0 2 concentration and the 
rate of softening of the fruit. An atmosphere containing even 5 per cent 
C0 2 resulted in a distinctly slower rate of softening than did air of the 
normal concentration, while higher concentrations resulted in still further 
decreasing the softening rate. Acidity, on the other hand, apparently, 
disappeared more rapidly at the higher concentrations of C 0 2 . While 
the acidity results are all so close together that they are not at all con¬ 
clusive, the uniformity of the fruit used in these tests as well as the 
regularity of the results makes them very suggestive. Results of a 
similar series of tests on Delicious apples are recorded in Table XI. 
Table XI.* —Relative hardness and acidity in Delicious apples after being held 11 days at 
71. 5 0 F. (22 0 C.) in various concentrations of C 0 2 . a 
Description of test. 
Acidity — 
Lot No. 
! 
Per cent 
CO?. 
f 
Per cent Oa. 
I 
Pressure 
test. 
cc. N/10 acid 
per 10 gm. 
wet tissue. 
3 
1 .. i 
r 
0 
20 
i 
Pounds. 
11.78 ! 
12.31 | 
12.63 j 
13.821 
13 - 58 1 
i 3 - 58 | 
i 
1 
2. 26 
2. 
I C 
20 
: 2.43 
2.31 
2.21 
2. 
IO 
20 
A .. 
20 
20 
C. 
50 
IOO 
1 
20 
2.26 
6. 
O 
2.22 
: 
a Removed from storage at 32 0 F. at beginning of test. Pressure test, 13.68 pounds. Acidity, 2.36 cc. 
N/10 acid per 10 grams of wet tissue when removed from storage at 32° F 
73430—24-3 
