SmartFresh™ Maintains Firmness 

 and Delays the Onset of Senescent 

 Breakdown in IVIacoun Apples 



Renae E. Moran and Patricia McManus 



Highmoor Farm Agricultural Experiment Station, University of Maine 



Macoun, a high-value apple cultivar in New 

 England, has high consumer appeal because of its 

 flavor, but loses its appeal within a few months of 

 harvest because of rapid softening, hi addition to 

 softening, Macoun is prone to senescent breakdown, 

 typically succumbing after two to three months in 

 regular air storage. As a result, production remains 

 less than 10% of the total m New England. We tested 

 SmartFresh effectiveness in maintaining fiminess of 

 Macoun harvested at different maturities and stored in 

 regular air. 



Materials & Methods 



Macoun apples were harvested at two different 

 dates in three years: September 24 and October 4 in 

 200 1 , October 7 and 1 5 m 2002, and October 1 and 8 in 

 2003. Fruit were harvested from frees on various 

 dwarf rootstocks. Flesh fmnness and starch index 

 were measured on ten fruit at each date. The Cornell 

 Starch Chart was used where 1 = all starch remainmg 

 and 8 = no starch. Internal ethylene concentration at 

 harvest was measured in ten fruit in 2002 and 2003. 



Apples were exposed to 1 ppm of SmartFresh 

 within 24 hours of harvest. Fruit were stored at 37°F in 

 regular afr for 100 days in 2001. hi 2002 and 2003, 

 fruit were stored at 34°F in regular air for 50 and 90 

 days. Following storage, fruit were kept at 68°F for 

 one and seven days when firmness and disorders were 

 measured. 



Results 



\n 2001, starch index was 3.0 at the first harvest 



and 5.6 at the second. Following four months storage 

 and seven days at 68°F, SmartFresh maintained 

 fiminess in fruit from the first harvest (12 lbs.) above 

 the firmness of untreated fruit (1 1 lbs.). This did not 

 occur with the second harvest when fiminess was 10 

 lbs. in both treated and unfreated fruit. Fruit from the 

 second harvest were too mature for SmartFresh to be 

 effective for as long as 100 days in regular air. The 

 effect of SmartFresh is temporaiy, becoming 

 undetectable after several months in regular air 

 storage, hi this study, the effect on firmness did not 

 last 100 days in overmature fruit. 



hi 2002, starch index was 3.1 at the first harvest 

 and 4.9 at the second. hitemal ethylene was 

 undetectable at the first harvest and 29 ppm at the 

 second. An apple is considered too mature for long- 

 temi storage when the internal ethylene rises above 1 

 ppm. hi 2002, SmartFresh maintained firmness above 

 that of untreated fruit after 50 and 90 days, but was 

 more effective in fruit from the first harvest (Figure 1 ). 

 After 50 days, fiminess was gi'eater by 4 lbs. in first- 

 harvest fruit, but only by 2 lbs in second-harvest fruit. 

 After 90 days, fiminess of first harvest fmit was 

 greater by 3 lbs., but only by 1 lbs. in second harvest 

 fmit. 



hi 2003, starch index was 2.7 at the first harvest 

 and 3.5 at the second. Ethylene was 4 ppm at the first 

 harvest and 1 ppm at the second. Finmiess in 2003 

 followed a similar pattern as in 2002. Fiminess was 

 maintained 4-5 lbs. above untreated fruit with the first 

 harvest and 2-3 lbs. with the second. 



Minimum acceptable fiminess by consumers is 

 considered to be about 12 lbs. and optimum firmness 

 about 15 lbs. SmartFresh maintained fiminess near 



12 



Fruit Notes, Volume 69, Summer, 2004 



