34 



BULLETIN" 1406, U. S. DEPARTMENT OF AGBICULTUEE 



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SOFTENING OF APPLES HELD AT VARIOUS TEMPERATURES 



Durino- the season of 1924-25 a number of apple varieties were 

 placed in storage at temperatures of 30°, 32°, 36°, 40°, 50°, 60° ? and 

 70° F., respectively. The softening rates of some of these varieties 

 at this wide range of temperature are shown in Figures 14 to 20. 



Aside from the comparison 

 of softening rates of different 

 varieties, which has been dis- 

 cussed under the rate of soft- 

 w ening at 32°, 40°, and 70° F., 

 ^ s&r ocr aw && aw it is oi primary interest to 



Fig. 14.— Softening of Virginia-grown Mcintosh Compare the rate of Softening 



apples in storage at various temperatures, j n the same variety at the dif- 

 ferent storage temperatures. 

 A comparison of all the charts will show that softening at 60° is only 

 slightly slower than at 70°. On the average, about one-third longer 

 was required for fruit to reach prime eating condition when held at 

 60° than was required for similar fruit when held at 70°. 



The softening rate of practically all varieties held at 50° F. was 

 approximately one-half as fast as when held at 70°. It is thus 

 apparent that there is a dis- 

 tinctly greater difference in | 

 softening rate between 50° and V 6 

 60° than there is between 60° \" 

 and 70°. At 40° the softening k* 

 rate averages slightly over one- \/o 

 half the rate at 50°, or approxi- 

 mated one-fourth the rate 

 at 70°. 



At 32° F. softening in most 

 varieties was slightly less than 

 half as rapid as at 40° ; at a temperature of 36° the softening rate is 

 intermediate between 32° and 40°. 



The comparative rates of softening at 30° and at 32° F. are very 

 interesting. Most varieties required 20 to 30 days longer to reach 

 prime eating condition when held at 30° than similar fruit held con- 

 tinuously at 32°. The temperatures in these two rooms were very 





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Fig. 15. — Softening of Virginia-grown Grimes 

 Golden apples in storage at various tem- 

 peratures, 1924—25 



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Fig. 16. — Softening of Virginia-grown Stayman Winesap apples in storage at va- 

 rious temperatures, 1924-25 



accurately controlled, so that the slower softening rate at 30° is a 

 real index of the effect of small differences in temperature when 

 the storage-room temperature is close to the minimum. At 32° the 

 fruit softened approximately 25 per cent faster than at 30°. 



To summarize the softening data, then, it may be "stated that at 

 32° F. the apple varieties on the whole softened about 25 per cent 



