HANDLING APPLES FROM TREE TO TABLE 13 



Gas Storage 



In England, some varieties of apples, particularly the leading cooking 

 variety, Bramley's Seedling, in ordinary cold storage develop low-tem- 

 perature breakdown. The same is true to a limited extent in cer- 

 tain parts of the United States, particularly with Yellow Newtown 

 apples in the Pajaro Valley, Calif., and with Mcintosh in New York 

 State, in which brown core may develop excessively during storage at 

 32° F. The gas-storage method was developed by Kidd and West (12) 

 in England to meet this problem. The method calls for an airtight 

 storage chamber, in which the carbon dioxide produced in the respira- 

 tion of the apples is allowed to build up to the desired concentration 

 while the oxygen content of the storage air is reduced. The temperature 

 of the storage room is usually held at 40° ; so refrigeration is required in 

 addition to the gas treatment. Because varieties differ in their response 

 to different ratios of carbon dioxide to oxygen, separate chambers may 

 be required for different varieties. The desired ratio is obtained either 

 by pumping the storage air through a lye solution to absorb the excess 

 carbon dioxide or by ventilating the chamber periodically to admit fresh 

 air and build up the oxygen. As the vast bulk of the American apple 

 crop can be held satisfactorily in cold storage and most varieties are not 

 benefited by the gas treatment, it is not likely that this method of stor- 

 age will have wide application in this country because of the added cost 

 and extra work that it entails. However, for special situations it may 

 be utilized profitably despite the extra cost. Several gas storage rooms 

 have been put into operation in New York for the storage of Mcintosh 

 apples in accordance with the recommendations of Smock and Van 

 Doren (26). 



Atmospheric Humidity 



Keeping the apples from wilting and shriveling is as important as 

 keeping them from getting overripe. It can be done by controlling the 

 humidity in the storage space. A certain amount of moisture is con- 

 tinuously lost by the apples through the process of transpiration (evap- 

 oration) . 



Although evaporation can be cut down by reducing the temperature, 

 it is particularly serious in apples which are not properly matured and on 

 which lenticels are not normally corked over and the wax coating is not 

 sufficiently developed. The natural barrier to loss through evaporation 

 is the waxy skin of the fruit. Any injury to the skin or the removal of 

 the wax, as in some washing processes, facilitates moisture loss and in- 

 creases the severity of wilting. Careful handling to avoid bruising and 

 injury of the skin and the use of proper washing processes are important 

 therefore in preventing excessive wilting or shrinkage in storage, as well 

 as blue mold rot and other types of decay. The drier the air the greater 

 is the degree of wilting. If the relative humidity of the storage is main- 

 tained at 85 percent or higher, which is the approximate water content 

 of apples, the pull on the fruit for moisture, or the evaporating power 

 of the air, will be slight and shrinkage of the fruit will be correspondingly 

 lessened. Where the relative humidity of the storage air is below opti- 

 mum, the faster the air is moved over apples the more moisture will be 



