i a 
Journal of Agricultural Research 
Vol. XXVII, No. i 
picking. Softening, already under way while the fruit was on the tree, 
proceeds rapidly after removal from the tree, unless the fruit is placed 
at once in a low temperature. 
The chemical changes in progress when the fruit is picked from the 
tree continue mainly in the same direction after picking, though the 
rate of the various changes may not be the same. From time of picking 
forward, there is a continuous drop in acidity. Starch present in the 
fruit quickly changes to sugar, as has been shown by the work of Bigelow, 
Gore, and Howard (2 ), of Otto (22 ), of Magness and Burroughs. 5 Follow¬ 
ing completion of this change, there is little further variation in total 
sugars, although there is undoubtedly a very small loss due to respiration. 
Even this loss may be partially replaced by acquisitions from the pectin 
materials. Bigelow, Gore, and Howard found that as the fruit was held 
in storage there was a continual decrease in the percentage of sucrose 
and a corresponding increase in reducing sugar. Pectin changes, asso¬ 
ciated with the softening of the fruit, continue throughout the storage 
season. 
EFFECT OF STORAGE CONDITIONS UPON CHANGES IN FRUIT FOLLOWING 
PICKING 
Among the conditions in storage houses that are within the control 
of the operator or fruit handler may be included the factors of tempera¬ 
ture, humidity, air renewal, or ventilation, air stirring or movement 
within the room, and the type of package in which the fruit is packed. 
These factors have been studied in relation to their effect upon certain 
of the changes occurring in the fruit while in storage. The studies have 
consisted primarily in determining the effect of these different factors 
upon the rate of softening of the fruit, upon the acidity changes in the 
fruit, and upon the general metabolic activity as measured by respiratory 
activity. Shrinkage in weight, due to loss of moisture from the fruit 
and loss through respiratory activity, has also been studied. 
EFFECT OF TEMPERATURE OF STORAGE UPON RATE OF SOFTENING 
Magness and Burroughs 6 * 8 measured the rate of softening of eight 
varieties of apples under different storage conditions. Composite curves, 
from their data on Jonathan, Delicious, Rome Beauty, Winesap, Bald¬ 
win, York Imperial, Esopus (Spitzenberg), and Yellow Newtown, at 
36° and 32 0 are reproduced in Figure 5. It will be noted that the rate 
of softening in storage was approximately exactly twice as rapid at 36° 
as at 32 0 F., fruit at 36° being as soft after two months in storage as fruit 
at 32 0 was at the end of four months. 
Figures 6 to 11, inclusive, show the relative rates of softening of Deli¬ 
cious, Rome Beauty, Ben Davis, Rhode Island Greening, Winesap, and 
York Imperial, respectively, when held at 70° F. and at 32 0 F. Figures 
6, 7, and 8, for the first three named varieties include data on fruit picked 
at three different intervals, approximately two weeks apart. 
It is at once apparent that softening in all varieties was greatly acceler¬ 
ated by higher temperatures. However, it is also apparent that there 
is a distinct difference in the response of different varieties to the various 
temperatures. 
6 Magness, J. R., and Burroughs, A. M. appus storage investigations. The Marble labora¬ 
tory, Inc. 2d Rept. Not yet published. 
8 Magness, J. R., and Burroughs, A. M. op. cit. 
