ISHS Acta Horticulturae 343: Physiological Basis of Postharvest Technologies
TOLERANCE OF CUCUMBER FRUIT TO IMMERSION IN HEATED WATER AND SUBSEQUENT EFFECTS ON CHILLING TOLERANCE |
| Authors: | T.G. McCollum, R.E. McDonald |
| Abstract:
High-temperature conditioning treatments have been reported to enhance the chilling tolerance of a number of chilling-sensitive tissues. We are interested in determining if immersion in high-temperature water will enhance the chilling tolerance of cucumber fruit. Our objective in this work was to determine the tolerance of cucumber fruit to immersion in heated water, and subsequent effects on chilling tolerance. Electrolyte leakage and activity of ethylene forming enzyme (EFE) were used as indices of thermotolerance. Cucumber fruit, following a 30 min immersion, exhibited significantly reduced EFE activity with increasing water temperature over the range of 25 to 54C. Inhibition of EFE activity was greatest immediately following immersion. Significant recovery of EFE activity during 48 hr following treatment occurred in fruit immersed at 46 and 50C, but not 54C. Water temperature did not affect electrolyte leakage following a 30 min immersion. Increasing duration of immersion from 30 to 90 min at 42C resulted in an increased inhibition of EFE activity and enhanced electrolyte leakage. Air-filled cavities were also observed in fruit held at 42C for 90 min. Fruit immersed in 42C water for 30, 45, or 60 min prior to storage at 2.5C for 1, 2, or 3 weeks had less electrolyte leakage than did nontreated fruit, indicating that immersion in 42C water can increase chilling tolerance in cucumbers. | |
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