Table 5. Effects of 1-MCP on internal ethylene concentration and fruit 

 firmness on Spigold apples harvested October 22 following 32F air storage 

 for 90 or 150 days, each followed by 1 week at 70F to evaluate shelf life. 



90 days cold storage 1 50 days cold storage 



1-MCP 

 applied 



At harvest 



1 day 

 warm 



7 days 

 warm 



1 day 

 warm 



7 days 

 warm 



Check 

 1-MCP 



Check 

 1-MCP 



31 



14.6 



Internal ethylene concentration (ppm) 



180 359 209 



49 39 64 



Firmness (pounds) 



10.2 10.0 9.4 



11.0 11.8 10.6 



384 

 185 



9.1 



10.0 



treatment for at least 150 days in Gala. Ethylene 

 production in 1-MCP treated Mcintosh reached levels 

 of control fruit by 1 75 days of cold storage in fruit 

 which had not been treated with Retain"". Weight loss 

 during cold storage was significantly reduced in 

 Delicious, and weight loss during a week at room 

 temperature following cold storage was reduced by 1- 

 MCP treatment of Mcintosh (data not shown) and 

 Delicious. A very significant result was that all 

 cultivars harvested on different dates showed the same 

 results between harvest dates, except that changes that 

 occurred before harvest were not reversed. Thus, 1- 

 MCP had some benefit regardless of ripeness at 

 harvest. Two important effects were not measured. 

 We did not measure volatile production (or aroma), 

 although we did observe that aroma was lacking in the 

 1 -MCP-treated Gala following storage. We did not do 

 taste tests, as the product is not registered for use. The 

 only 1 -MCP-treated fruit which fully recovered 

 ethylene production were the non-Retain™ Mcintosh 

 harvested on September 10 and stored for 175 days in 

 32F air. Even these fruit retained their firmness 



advantage over untreated fruit 

 and did not develop superficial 

 scald as the other fruit did. The 

 Ginger Gold, Retain'"-treated 

 Mcintosh, Delicious, and 

 Spigold which had been treated 

 with 1-MCP all started produc- 

 ing more ethylene after a time in 

 storage, but did not come close 

 to catching up with their 

 untreated counterparts. 



Based on this preliminary 

 investigation, 1 -MCP treatment 

 appears promising for increased 

 firmness retention in a broad 

 spectrum of apple cultivars, 

 including Mcintosh as well as 

 for scald control. We observed 

 scald only on Mcintosh m this 

 study, but others have observed 

 similar results on other cultivars, so a general response 

 may exist although further tests are essential. Since 

 maximum 1-MCP effect may depend on early harvest, 

 at least in some cultivars, scald protection would be an 

 extremely valuable benefit. Combining 1-MCP 

 treatment with CA might enhance the effect of either 

 one alone. Taste tests will be essential to determine if 

 the firmness advantage is offset by losses in flavor or 

 aroma. If so, this is likely to be cultivar dependent. 

 Seasonal variation in effectiveness of 1 -MCP has been 

 reported, so we need to determine how repeatable 

 these results are. Finally it remains to be determined 

 how 1-MCP can be applied efficiently on a 

 commercial scale. Nevertheless, despite these issues, 

 this is an extremely interesting new material. 



A cknowledgm ent 



We would like to thank Harlow Warner of 

 AgroFresh, Inc . for supplying the 1-MCP used in these 

 experiments. 



it it it it it 



Fruit Notes, Volume 67, Summer, 2002 



