Aug. 1, 1924 
Freezing Injury of Apples 
119 
comes very pronounced in this variety 
after a certain amount of freezing, but 
discoloration does not appear so com¬ 
monly (Table X). 
It will be noted that there is some 
variation in the amount of injury to 
different varieties when they are" ex¬ 
posed for the same periods of time to 
freezing temperatures such as prevailed 
during the experiment. The small 
amount of visual injury found in De¬ 
licious apples, as a rule, is an example 
of this variation. Hence, the periods 
of time for which apples in packages 
may be exposed without serious de¬ 
preciation in immediate market value 
will differ not only with the variety, 
but with the changing factors in pack¬ 
ing, handling, and other conditions 
which we are not yet able to recognize. 
In general, it may be said that for 
temperatures such as prevailed during 
these tests, which averaged between 
tures from 21° to 23.5° F. for different 
lengths of time. Data are also given 
for Delicious apples, exposed in boxes 
as originally packed, to freezing-room 
temperatures from 20.5° to 24°, 
averaging 22° most of the time. 
Wrappers were removed from the 
latter apples in some boxes, but this 
packing arrangement was not otherwise 
disturbed. After exposure to these 
temperatures for the required time both 
groups of apples were held at 65° for 
three days before examination. 
A comparison of results with wrapped 
and unwrapped lots, shown in Table 
XI, indicates that wrapping markedly 
retards visual injury. For instance, 
the percentage of injury for unwrapped 
Delicious apples exposed five days is 
not radically different from that for 
wrapped apples exposed nine days. 
There is a similar difference if 7-day 
wrapped fruit is compared with 12-day 
Table XI.— The effect of wrapping fruit on the amount of visual injury in Yellow 
Newtown and Delicious apples after exposure to freezing temperatures averaging 
22° F. for various lengths of time 
Percentage of visual injury 
Total 
Period of exposure 
Wrapped or unwrapped 
number 
None 
Trace 
Severe 
of apples 
YELLOW NEWTOWN FROM VIRGINIA 
72 hours. 
72 hours. 
120 hours 
120 hours 
168 hours 
168 hours 
Unwrapped... 
89.7 
5.7 
4.6 
88 
Wrapped__ 
96.6 
3.4 
0 
88 
Unwrapped__ 
62.0 
14.0 
34.0 
100 
Wrapped_ 
88.4 
4.2 
7.4 
95 
Unwrapped_ 
29.5 
14.7 
55.8 
95 
Wrapped_ 
72.1 
9.7 
18.2 
93 
DELICIOUS FROM WASHINGTON 
72 hours.____ 
Unwrapped... 
97.4 
2.6 
0 
120 hours___ 
_do.. 
94. 7 
1.8 
3. 5 
168 hours... _ _ 
_do_.» ... 
66.3 
31.8 
1, 9 
208 hours_ _ 
Wrapped.. 
89.4 
10.6 
0 
288 hours... .. 
_do_ 
60.3 
35. 2 
4.5 
360 hours _ 
_do_ ____ 
0 
80.5 
19.5 1 
i 
i 
21° and 22° F., the exposure period 
must not be over 72 hours if serious 
damage is to be prevented and 48 
hours is a much safer figure for some 
varieties. The fruit here discussed 
was not wrapped. As shown below, 
wrapping may considerably extend 
the period during which fruit may be 
exposed to low temperature without 
injury. 
WRAPPING AS A RETARDANT OF FREEZ¬ 
ING INJURY 
Since it has been shown that wrap¬ 
ping materially retards the cooling in 
the fruit (see above, p. 110 to 111), it 
could be expected to reduce the amount 
of visual injury. Data are given in 
Table XI on the effect of exposing 
wrapped Yellow Newtown apples, 
packed in northwestern apple boxes, 
4-3 packs, 5 tiers high, to tempera- 
unwrapped fruit. These observations 
apply only to the amount of visual in¬ 
jury developed. 
Wrapping apples not only retards 
visual injury, but has other beneficial 
effects during thawing. It retards the 
rapid water loss which often takes 
place in the fruits, especially when 
thawing occurs at comparatively low 
humidities, and also lowers the amount of 
injury due to bruising while hard frozen, 
the latter feature being important if the 
fruit is hard frozen while in transit and 
subjected to jolting and jarring. 
EFFECT OF WILTING ON FREEZING INJURY 
Two collateral lots of Grimes Golden 
apples were picked early in the season, 
and one lot was subjected to freezing 
temperatures after only a short storage 
period at 32° F. The other lot was 
held in slat crates in storage at 32° 
