20 MASS. EXPERIMENT STATION BULLETIN 440 



This is the function of storage. No method has yet been discovered by 

 which life processes in an apple may be stopped and the apple held in- 

 definitely at one stage of development without killing it. The progression 

 must go on, but efficient storage slows it down to a marked degree. 



There is ample evidence that storage brings marked changes in apples. The 

 factors influencing the storage qualities of apples, according to Wallace (1930) 

 can be summarized as follows: 



(a) Material — variety and age of tree. 



(b) Environmental. These may be further divided into two subgroups: 



L Natural conditions — including the climatic factors, soil, pests, 



fungi, etc. 

 2. Artificial factors introduced by the grower — • including soil treatment, 



other operations, picking, and handling. 



Carlsen (1946) reported that a gradual reduction of temperature from 45° to 

 36° to 31° F. will keep Delicious apples in better condition than any other prac- 

 tice, except immediate storage at 31° F. The age of the apple afteV picking can 

 be measured by the structural changes within the apple as shown by increases in 

 the soluble pectin content determined by chemical analyses. The softening of the 

 flesh which accompanies ripening or maturity is due to gradual increase in the 

 soluble pectin content. These changes take place much more rapidly and com- 

 pletely in so-called early and summer varieties such as Yellow Transparent, Red 

 Astrachan, Williams, etc. The rate of softening is closely related to temperature 

 of storage. 



Fellers, Cleveland and Clague (1933) found that apples tend to decrease in 

 ascorbic acid content during storage. This change varies to some degree with 

 the variety and takes place more rapidly at warm storage temperatures. Baldwin 

 apples had lost about 20 percent of their vitamin C content after 4 to 6 months' 

 storage at 36°F., and after 8 to 10 months the loss had reached nearly 40 per- 

 cent. At a storage temperature close to 32°F. there is but little loss of ascorbic 

 acid. At warmer storage temperatures the loss may be as much as 50 percent 

 after 6 to 8 months. According to Thornton (1938) no loss of ascorbic acid oc- 

 curred in apples stored in an atmosphere of carbon dioxide. Todhunter (1937) 

 found that Delicious apples kept for one year at 45 °F. retained approximately 

 only half of their original vitamin C content. Other investigators have reported 

 similar findings in respect to changes in the ascorbic acid content of apples during 

 storage. 



EFFECT OF PROCESSING AND COOKING ON COMPOSITION AND 

 NUTRITIVE VALUE 



Cooking 



Apples tend to lose certain of their nutrients during cooking as do other foods. 

 So far as the apple is concerned, ascorbic acid (vitamin C) is probably the nu- 

 tritive element that shows the greatest change during cooking. The other 

 nutrients can be expected to be quite stable with the exception that some water- 

 soluble materials may be leached from the apple If It is cooked in an excess of 

 water or syrup. However, ordinarily apples are not cooked by methods which 

 would lead to an excessive leaching of nutrients. 



Fellers, Isham, and Smith (1933) and Todhunter (1935) found that a consider- 

 able amount of the original ascorbic acid of fresh apples was retained when they 



