104 
Journal of Agricultural Research 
Vol. XXIX, No. 3 
tected, and detracts from the appear¬ 
ance of the fruit, injuring its market 
value. Yellow Newtown apples so 
affected may appear to have been sub¬ 
jected to very severe bruising while in 
the hard frozen state. 
Time of appearance of visual 
INJURY IN FROZEN APPLE TISSUE.- 
The discoloration of apple tissue which 
follows a certain degree of freezing is 
generally not visible while the fruit is 
still frozen. As thawing proceeds, it 
becomes more and more evident. 
Where freezing is not severe it may 
increase in degree, and to a lesser extent 
in area, as the ice in the tissue melts 
(Table III). 
Table III.— Effect on Yellow Newtown 
apples {in lots of 10) of varying periods 
of exposure to 15° F ., and of different 
periods of storage at 40° and 65° after 
freezing 
Period of 
Number of apples showing injury in— 
exposure 
( 
5 hours 
8 hours 
13 hours ! 
90 hours 
Hours 
SUBSEQUENT STi 
ORAGE AT 65° F. 
3_ 
0 
0 
0 
4 
6. 
i 2 
2 
a 4 
° 5 
25_ 
i 10 
10 
10 
10 
47. 
' 10 
10 
10 
10 
73.. 
j 10 
10 
10 
10 
i SUBSEQUENT STORAGE AT 40° F. 
3.! 
0 
0 
“1 
a 2 
6_ 1 
0 
a 1 
a 2 
o5 
25..i 
*3 
“3 
a 7 
l0 
47.._ 
0 
a 5 
10 
10 
73_ 
0 
“7 
10 
10 
° Slight injury only. 
From Table III it is evident that the 
severity of the injury to Yellow New¬ 
town apples exposed for the shorter 
periods increases with the length of the 
storage period. It seems improbable, 
however, that it increases materially 
when the ice in the tissue has entirely 
melted; where such increase occurs it 
may be due to secondary influences in 
tissues weakened by freezing rather 
than to killing by the formation of ice. 
Thus it is apparent that when moderate 
freezing injury has occurred, it is im¬ 
possible to determine accurately the 
amount of injury until a considerable 
interval of time has elapsed following 
thawing. 
The term “baked” or “cooked” is 
frequently given to very severely 
frozen apples which break down com¬ 
pletely, actually presenting the brown, 
wrinkled appearance of an apple sub¬ 
jected to high temperature. Such sur¬ 
face injury is readily recognized. 
EFFECT OF BRUISING FROZEN APPLES 
The bruising of hard frozen apples 
results in a much more serious injury 
than that produced by similar bruising 
of unfrozen fruit. Some experiments 
were made to determine in what re¬ 
spects such bruises made while the fruit 
was frozen differed from the ordinary 
bruises; whether the freezing of bruises 
already present changed their appear¬ 
ance and depth; and whether the tem¬ 
perature of thawing had an effect on 
the seriousness of the bruise as meas¬ 
ured by its depth. 
The apple to be bruised was held 
on its side on the platform of a 
weighing scale having a capacity of 50 
pounds. A flat surface was brought in 
contact with the upper side of the fruit 
and pressure applied until the pointer 
on the dial recorded the desired figure 
in pounds. The apple was then turned 
and pressure again applied, thus pro¬ 
ducing four bruises fairly equally spaced 
about the circumference. While this 
does not give exactly the type of bruise 
encountered where the fruit has been 
subjected to jolting or bumping or has 
received sudden sharp blows rather 
than more prolonged pressure, it was 
found satisfactory for the investigation 
of certain features of this problem. 
After further storage or treatment, the 
apple was cut across the middle hori¬ 
zontally and the depth of the bruises 
determined in millimeters. The great¬ 
est distance to which the discoloration 
had penetrated was taken as the depth 
of the bruise. The sample lots con¬ 
sisted of 10 apples each having 4 bruises, 
and the data presented in Table IV are, 
in each case, averages of the maximum 
depth of 40 bruises. 
Differences in appearance of 
BRUISES ON HARD FROZEN AND ON UN¬ 
FROZEN apples. —Bruises made on 
apples while frozen differ in several 
respects from those on unfrozen fruit. 
The bruises in hard frozen apples have 
a greater depth and are conical in shape 
with the apex reaching nearer to the 
explanatory legend for plate 3 
A.—Cross section of Yellow Newtown apple, grown in Washington, showing extensive discoloration 
involving the tissue cells, and rather characteristic of this variety. A bruise discoloration is found near the 
periphery. A rather severely frozen specimen. 
B—Cross section of Grimes apple, grown in Virginia, showing extensive tissue-browning as well as 
discoloration of the cambial and carpel regions. A severely frozen specimen. 
