Market . A New England market for Asian 

 pears has already been established by Western 

 U.S. fruit marketers, but it is felt that a few 

 enterprising local growers could find a niche in 

 our markets for this group of fruits. 



Information for this article came from 

 Fowler Nurseries, Newcastle, CA, and from 

 articles in HortScience (15:13-17) and California 

 Agriculture (W. H. Griggs and B. T. Iwakiri. 

 January, 1977). 



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VARIABLE CONDITIONS IN CA STORAGE CAN 

 CAUSE FRUIT DISORDERS AFTER STORAGE 



William J. Bramlage 



Department of Plant and Soil Sciences, University of Massachusetts 



We frequently receive samples of fruit after 

 storage which contain some disorder(s), and are 

 asked what caused the problem. Even when we 

 see a copy of the storage log, it is often difficult 

 to specify the problem. We can usually identify 

 the disorder, but pinpointing its cause is often 

 little more than a guess, because storage (and 

 prestorage) conditions often interact to produce 

 problems. 



This interaction of conditions was addressed 

 in a recent paper by C. R. Little and I. D. Peggie 

 of the Horticultural Research Institute, Victoria, 

 Australia {HortScience 22(5):783-790). The paper 

 reported results from an extraordinarily complex 

 series of experiments that spanned 8 years and 

 included 7 cultivars of apples and 2 cultivars of 

 pears. All fruit were harvested preclimacteric and 

 were stored in small experimental chambers where 

 conditions could be carefully controlled. 



The primary objective was to test various 

 I0W-O2 regimes. In this experiment, they 



compared Conventional CA (2 to 5% CO2 and 2 to 

 5% O2, depending on cultivar). Ultra-low O2 (1% 

 CO2 and 1.5% O2), and Hyper-low O2 (0.5% CO2 

 and 0.7 to 1.0% O2). They also applied Initial 

 L0W-O2 Stress (less then 0.2% O2 and less than 

 2% CO2 for the first 10 days of storage), followed 

 by one of the other I0W-O2 systems. In addition 

 to comparing the various O2 regimes, they 

 examined the interaction of Rapid CA (at- 

 temperature 1 day after harvest and at- 

 atmosphere in less than 6 days after harvest), 



Slow CA (at-atmosphere 14 to 20 days after 

 harvest), inappropriate temperatures, high CO2 

 levels, and ethylene scrubbing. 



Results were judged in terms of the 

 percentages of disorders that occurred, primarily 

 scald, Hesh browning, and core flush (a disorder 

 somewhat similar to brown core in Mcintosh). 

 Most of the experiments were with Jonathan and 

 Granny Smith apples. 



Among the findings of the study were these: 



1. The lower the O2 level, the less scald 

 developed. However, below a certain O2 

 level (depending on cultivar), the percents of 

 flesh browning and core flush increased. At 

 these levels, off-flavor and purpling of the 

 skin were noticeable in some cultivars. 



2. Very low levels of O2 at the beginning of 

 storage were effective when Rapid CA was 

 used, but caused disorders when Slow CA 

 was used. Also, the Initial L0W-O2 stress 

 caused disorders if it lasted more than 10 

 days. 



3. If the atmosphere was changed part-way 

 through storage, it was beneficial if it 

 beoune less severe but was detrimental if it 

 became more severe. The change was more 

 consequential if it occurred at 100 days than 

 if it occurred later than this. 



15 



