FREEZING OF APPLES: HOW MUCH DAMAGE DOES IT CAUSE? 



W.J. Bramlage and R.E. Bir 

 Department of Plant and Soil Sciences 



In the fall of 1969, unusually early freezes occurred while 

 many apples were still in the orchard. Many questions were raised 

 about the effects of the freezing on apple quality and storage 

 life, and there was \/ery little firm evidence on which to base 

 answers , 



Most of the work that has been done on freezing of apples was 

 done many years ago, using freezing procedures and conditions that 

 are quite different from what happens in the orchard or during 

 storage. At the January, 1970, meeting of the New York State Hor- 

 ticultural Society, Dr. R.M. Smock of Cornell University summed up 

 ( Proc. N.Y. State Hort. Soc . 115:199-204) what was known about 

 freezing injury to apples and concluded that: 



Less damage occurs 

 the tree. 



to apples frozen on the tree than off 



2. Apples should never be handled while frozen. 



3. It is difficult to predict damage. 



4. Frozen apples should be sold as soon as possible. 



To learn more about freezing injury to apples, we conducted 

 an extensive series of tests last year using 'Richared Delicious' 

 apples. These apples were frozen under carefully controlled con- 

 ditions, their temperatures were constantly measured, and the ef- 

 fects of freezing on condition of the fruit were determined immed' 

 iately after freezing and after storage for 1-3 months at 32 F. 



We found that the apples had two freezing points (Fig. 1). 

 The fji^st one was at about 28 F and the second one was at about 

 23-24 F, although in some fruits it occurred somewhat lower than 

 this. We tested apples from August to mid-October and found that 

 the temperature of these freezing points did not change as the 

 fruits matured and ripened. This is the first time that more than 

 one freezing point has been seen in apples, and what makes this 

 finding important is that we learned that injury to the fruit is 

 very closely related to these freezing points. 



At the first freezing point, ice forms in the fruit and if 

 held long enough at this temperature the apples will become" frozen 

 solid." Any physical contact with the frozen apples will leave 

 brown, sunken "contact points" after thawing, probably because the 

 ice crystals pierce and kill the cells in the contact area. If 

 the apples are allowed to thaw they will survive this freezing 



