FREEZING INJURY OF FRUITS AND VEGETABLES 



25 



of ice between the skin and flesh. Softened, watery turnips were 

 found all the way to the bottom of the basket, but there were a few 

 that showed no signs of injury. In some of the injured specimens 

 the flesh had turned from white to light brown. 



RATES OF COOLING OF FRUITS AND VEGETABLES 



The rates of cooling of wrapped and unwrapped apples and of 

 topped carrots are given in figure 1, of wrapped and unwrapped 

 lemons in figure 2, and of rutabagas and cabbage in figure 3. 



35 



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Figure 1. — Rate of cooling of topped carrots and of wrapped and unwrapped 

 apples in packages not papered over the outside in an 18° F. room: 

 A, Apples; B, carrots. 



The following comments on the rate-of -cooling experiments and 

 the results will help to bring out facts shown by figures 1 to 3 ; they 

 also supplement the statements on apples (p. 5), cabbage (p. 12), 

 carrots (p. 13), lemons (p. 15), and rutabagas (p. 22). 



(1) Wrapped and unwrapped apples in eastern boxes at a start- 

 ing temperature of approximately 32° F. were placed in an 18° 

 room (fig. 1). The most exposed apples in both boxes (along the 

 edges, on top) began to freeze in about 3 hours after the test was 

 started. Freezing began after about 7 hours at the center of the 

 box of unwrapped fruit but not until after about 24 hours at the 

 same position in the box of wrapped fruit. 



(2) Topped carrots with a starting temperature of about 32° F. 

 in a lined standard crate with a pad under the lid were placed in an 

 18° room (fig. 1). Freezing began in exposed roots at the top in 

 about 3 hours but not until after about 6 hours at the center of the 

 crate. 



(3) Lemons in a standard California lemon crate were placed 

 in an 18° F. room (fig. 2) . The lemons in one-half of the box were 

 wrapped, whereas those in the other half were without wraps. 

 Their average starting temperature was approximately 32°. After 

 3 hours exposed lemons in the top layer, both wrapped and un- 

 wrapped, began to freeze on the outside. After 7 hours a few 



