Total Sugar 



For the varieties of mature apples in this study, total sugar content 

 ranged from approximately 54 to 62 percent of the total solids before 

 storage (fig. 5); Rome Beauty was lowest in total sugar; and the 

 other varieties in order of increasing amounts were Stayman, Delicious, 

 Jonathan, and Golden Delicious. Total sugar content in immature 

 apples before storage ranged from approximately 50 to 55 percent in 

 about the same order as the mature varieties. 



TOTAL SUGARS 



Percent of Total Solids 

 MATURE IMMATURE 



{• 



•— — Delicious 

 ■™ ^"" Golden Delicious 

 -• — » » Jonathan* 

 •••••• Rome Beauty 



^— X^™ Stayman 



% 



i i 



1 



i 1 







/** — ^ 



t~"*~ 



60 



_ / 



^^ 



AN 



V 





• 

 • 



55 



.-• 



• 



• 





// 





• 

 • 

 • 

 * 





/.-■ 





• 

 • 

 • 



50 



b 



_J__^_ 



• 



US DEPARTMENT OF AGRICULTURE 



6 3 6 



MONTHS 



* IMMATURE APPLES NOT STUDIED 



NEG 5580-58(10) AGRICULTURAL RESEARCH SERVICE 



Figure 5. — Total sugar content of mature and immature apples, before and after 



storage at 40° F., for 1 crop year. 



Although the total sugar content of mature apples, in general, was 

 not significantly affected by storage time, the differences in values 

 indicated increases in some varieties in the first 3 months of storage 

 followed by slight decreases with longer storage. Immature apples 

 of all varieties increased in total sugar during the first 3 months of 

 storage and in all but one variety decreased after 5 and 7 months of 

 storage. In a study of carbohydrate metabolism of stored Mcintosh 

 apples, Krotkov and Helson (19) found that the total sugar increased 

 from August until October or November when respiration reached its 

 peak, then decreased corresponding to the decline in respiration. 

 Plagge, Maney, and Gerhardt (35), in a study of physical and chemical 

 changes in Grimes apples, reported increases in sugar during storage. 



Mature apples stored at 32° F. showed approximately the same 

 trend in total sugar content as those at 40°, with a few exceptions, 

 which made a significant difference in results. After storage of 7 

 months, Delicious and Stayman apples showed a greater increase in 

 total sugar at 40°, whereas Rome Beauty apples showed a considerable 

 decrease at 32°. 



The correlation coefficient between total sugar and reducing sugar 

 was +0.39 representing data from the second crop only. Although 



31 



