BUREAU OF PLANT INDUSTRY. 175 



FACTORS AFFECTING THE STORAGE LIFE OF FRUITS. 



Fruit-storage activities liave been directed toward a study of the 

 behavior and ripening of Bartlett pears when picked at different 

 times and stored at different temperatures, a continuation of the 

 study of the interior browning of Yellow Xewtown apples grown in 

 the Watson ville district in California, frost-injury work based on a 

 determination of the freezing points of different fruits, the effect of 

 holding the material at different temperatures for different lengths 

 of time, Satsuma orange curing, grapefruit storage experiments, and 

 various activities of relatively minor importance. 



The work with Bartlett pears was carried on ijiincipally in Cali- 

 fornia with fruit produced in the Yakima Valley, Wash., in the 

 Rogue Eiver Valley in Oregon, and in California. In general, the 

 results of the work" in 1919 have shown that hard-ripe Bartlett pears 

 can be stored for two months or more at a temperature ranging 

 from 28° to 30° F. and that the fruit will be in good condition at 

 the end of this period. From analyses of the fruit it has been shown 

 that the sugar content and the dry matter increased the longer the 

 pears were allowed to remain on the tree. 



Further, it was found that there was considerable difference in the 

 acid content of fruit from the different regions, the more northerly 

 groAvn fruit apparently possessing more acid than that grown in 

 California. Whether this is a constant difference or wdiether it is 

 seasonal can be determined only by further work. The investiga- 

 tions are being continued the current season. 



The studies of apple browning in the Watsonville district have 

 been in progress for n considerable number of years. However, no 

 definite cause of the trouble can yet be assigned. Work is being con- 

 tinued along several different leads which have appeared as the work 

 has progressed. Certain beliefs which have been held from time to 

 time have been disproved: for instance, that there is some correla- 

 tion between the acidity of the fruit and the browning. 



Experiments in the curing of Satsuma oranges were carried on last 

 season in Baldwin County, Ala., where the Satsuma orange industry 

 is on a better commercial basis than it is in some other parts of the 

 Gulf coast region. This type of orange reaches its highest quality 

 for consumption some weeks before it attains a yellow color. If 

 allowed to remain on the tree until it is colored, it has a tendency to 

 become flat and tasteless. It has been shown through laboratory 

 tests and by experiments carried out on a fairly large scale in Ala- 

 bama that by exposing the fruit to an atmosphere of gases formed by 

 the imperfect combustion of kerosene and certain other petroleum 

 products, it will develop a desirable color in four or five days. The 

 marketing of fruit so cured resulted in sales at a somewhat liigher 

 price tlian the uncured fruit of the same grade. 



The storngt' work with grapefruit showed that fruits differently 

 handled behaved very differently in storage. As to the details, it 

 has been found that the acid content of grapefruit decren^:es during 

 storage, while the sugar content apparently remains practically the 

 same at all storage temperatures used. Fruit was stored at 32°. 30°. 

 40°, and at common storage (about G0° F.). The bitter principle of 



