28 MISC. PUBLICATION 16 8, U.S. DEPT. OF AGRICULTURE 



at 32° and 72° F. show an equal amount of injury, and (2) that in 

 a packed box or barrel slowly frozen apples show more discoloration 

 when thawed slowly (at 32°) than when thawed rapidly (at 50° or 

 higher). 



Apples that have been frozen are often dry and mealy, probably 

 because of loss of water through evaporation from the injured tissues. 

 The degree of mealiness increases with the amount of freezing but 

 is not entirely absent even when freezing was only slight. The flesh 

 sometimes apjDears flaky or corky and always lacks the normal crisp- 

 ness; in severeh^ frozen specimens it collapses and becomes viscid, 

 soft, and mushy. 



If apples are frozen but not " frozen to death " they may thaw out 

 with no apparent aftereffect except a slight softening of the flesh. 

 This softening, however, means that their prospective storage life 

 has been shortened. The amount of the reduction will depend on 

 the variety, the degree of maturity of the fruit when frozen, and the 

 severity of the freezing. There is no doubt that apples that have 

 been solidlj^ frozen throughout, even though for only a short time, 

 will not hold up so well in storage, or for so long a time, as similar 

 apples from the same orchard or the same storage lot or shipment 

 that have not been frozen. 



Apples should not be handled while they are frozen, because of 

 the danger of serious damage from bruising. Bruises produced in 

 this way frequently extend deep into the fruit, and the affected flesh 

 is usualh^ brown, soft, and somewhat watery. 



FREEZING INJURY AND INTERNAL BREAKDOWN 



During January or even earlier, and continuing through the re- 

 mainder of the storage season, it ma}^ sometimes be difficult to dis- 

 tinguish between freezing injury and the condition known as internal 

 breakdown due to overripeness. The difficulty will be greatest when 

 there is no evidence of freezing in transit. Internal breakdown may 

 be followed by browning, but the color change, unlike that which 

 often follows freezing injury, does not begin in the main fibro vascu- 

 lar bundles (in cross section, the 10 dots that surround the core). 

 Instead, it may begin at any place in the flesh and usually does 

 begin at many places. Seen in cross section, fruits affected with 

 internal breakdown often show the following conditions: An outer 

 shell of healthy flesh about a quarter of an inch thick surrounding a 

 brown zone which extends inward in roughly triangular patches as 

 far as the bundles or a little beyond; next to this is another zone 

 of healthy flesh, and in the flesh at the core is a second area of brown. 



In the Winesap overripeness is not usually followed by internal 

 breakdown and browning. Specimens of this variety held at 32° to 

 35° F. for more than 21 months were at the end of that time still free 

 from both of these conditions. They did show, however, a loose, 

 wrinkled condition of the skin which suggested freezing injury but 

 was probably caused by normal loss of water. 



Internal breakdown is usually worse in large-sized apples and 

 more marked at the blossom end than at the stem end. Freezing 

 injury may affect apples of any size and is not necessarily or uni- 

 formly worse at one end of an apple than at the other. Yet when 

 one side of an apple or even the whole apple shows in cross section 



