significant at the 5-percent level, it was a low correlation. Coefficients 

 of correlation between total sugar and total acidity and total sugar 

 and pH were too small to be of any consequence. 



Total Pectin 



Total pectin content of freshly harvested mature apples ranged 

 from 3.92 percent for the Golden Delicious variety to 4.89 percent, 

 for the Delicious variety. For the other four varieties it ranged from 

 4.10 to 4.50 percent. Storage at either 32° or 40° F. had little or no 

 effect on the total pectin content of mature apples. Although the 

 differences in total pectin content were statistically significant for the 

 varieties of apples from the first crop and for the effect of storage 

 time in the second crop year, these differences were extremely small 

 and did not show any consistent trend in both years. 



Immature apples contained from 3.98 to 4.95 percent total pectin 

 before storage and there were no significant differences among the 

 four varieties stored at 32° or at 40° F. for various lengths of time. 



Correlation coefficients for total pectin content and total acidity, 

 pH, or reducing sugar were not significant. Although the correlation 

 coefficient of —0.45 between total pectin and total sugar was sta- 

 tistically significant, it was too low to be of practical importance. 



Pectic Acid 



Since the pectic acid content of apples obtained in the two con- 

 secutive crop years differed, results are shown graphically for com- 

 parison in figure 6. The pectic acid content of freshly harvested 

 apples was lower in the second crop year (range of 0.33 to 1.25 percent) 

 than in the first (range of 0.56 to 1.36 percent). Differences in the 



PECTIC ACID 



1948* (MATURE) 1949* (MATURE) 



% 



0.5 



/ _ Delicious 



S •■ __ Golden Delicious 



-• — • — •- Jonathan 



••••• Rome Beauty 



X^™ Stayman 

 ■■■■ Winesap 



■ I ■ ■ I 



U — ' 



J L 



1 ' 



1949 (IMMATURE) 



1 ' 1 ' 



1 1 



/ 







S 



mx^^m>x 



s 



- / . 



• — 

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 • • 



//^ 



• 

 • _ 



-// // 



^^* 





• 

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i 



• 

 • 



■' ■ • 1 ■ 



, 1 



U.S. DEPARTMENT OF AGRICULTURE 



6 3 6 3 6 



MONTHS 



*CROP YEAR 



NE6 5581-58(10) AGRICULTURAL RESEARCH SERVICE 



Figure 6. — Pectic acid content of mature and immature apples before and after 



storage at 40° F. 



32 



