Aug. 1, 1924 
Freezing In jury of Apples 
109 
tures than will Winesap and Rome 
Beauty. Under the conditions of this 
test, actual internal temperatures of 
25° F. or lower were required to injure 
Ben Davis. An internal temperature 
of 26° resulted in some injury to Wine- 
sap, while 27° was sufficient to' result 
in slight injury to Rome Beauty. 
Below these temperatures, injury in¬ 
creased markedly with successive de¬ 
creases in temperature. The lower the 
temperature attained, the greater the 
quantity of ice formed in the tissues 
and the greater the apparent injury. 
These temperatures represent about 
the range at which visual injury will 
THE RATE OF COOLING DOWN OF BARRELS 
AND BOXES OF APPLES AT DIFFERENT 
FREEZING TEMPERATURES 
It is reasonable to suppose that tem¬ 
perature curves showing the rate of cool¬ 
ing of fruit packed in various types of 
containers would differ under constant' 
lbw temperature conditions outside the 
package. To obtain more evidence on 
this point, Winesap and York Imperial 
apples were exposed to freezing tempera¬ 
tures in barrels and in commercial apple 
boxes. The barrels were placed on 
end and the boxes were laid horizon¬ 
tally on a wooden floor rack 6 inches 
above the floor of the room. Part of 
Fig. 2—Temperatures obtaining in different parts of a barrel of unwrapped Winesap apples 
during exposure to external temperatures around 25° F. for 120 hours 
first occur when the apples thaw rather 
slowly in air temperatures. Certain 
data subsequently secured indicate 
that with extremely rapid thawing, 
such as that induced by immersing the 
frozen apples in warm water, visual 
injury may occur at somewhat higher 
temperatures. Internal temperatures 
even one degree below the freezing 
point may result in injury if followed 
by extremely rapid thawing. For 
commercial conditions, however, where 
thawing would always be in air, actual 
fruit temperatures of 25° to 27° repre¬ 
sent about the highest point at which 
visual injury may be expected to occur. 
the boxed apples were wrapped and 
part unwrapped. One series was run 
at about 25° F. and another at about 
20°. The reduction in temperature 
within the packages was read by 
thermocouples every two or three 
hours during at least four or five days, 
and in some instances this was carried 
on at longer intervals to 12 days. In 
this way a complete history was se¬ 
cured of temperature changes in the 
fruit in different portions of the pack¬ 
ages and in the surrounding air. The 
graphs presented in Figures 2 to 12 
show the temperature changes occurring 
in the apples. 5 
6 The preparation of the packages for these experiments was as follows: Two thermocouples were inserted 
in apples in each of the following locations in the packages: Barrel: Top, center, side at center and bottom. 
Boxes of wrapped and unwrapped apples: Top, center, and bottom. The two readings from the sam e 
location were averaged for better comparison of the data. 
