ISHS Acta Horticulturae 682: V International Postharvest Symposium
VAPOR PRESSURE DEFICIT AND WATER LOSS PATTERNS DURING SIMULATED AIR SHIPMENT AND STORAGE OF BEIT ALPHA CUCUMBERS |
| Authors: | E. Laurin, J.P. Émond, M.C.N. Nunes, J.K. Brecht |
| Keywords: | Cucumis sativus, low pressure, stress response, fruit quality, cucumber, water diffusion, airfreight, postharvest physiology |
| DOI: | 10.17660/ActaHortic.2005.682.226 |
| Abstract:
Harvested commodities lose moisture by transpiration, with the rate of loss affected by environmental factors such as temperature (T), relative humidity (RH), and atmospheric pressure (P). Commodities are commonly exposed to high T, low P, and large vapor pressure deficit (VPD) during air shipment, which can increase the transpiration rate and result in undesirable loss of moisture. The objective of this work was to understand the VPD and water loss patterns of Beit Alpha cucumbers in airtight and non-airtight containers during flight. To simulate flight conditions, cucumbers previously equilibrated to 4°C were stored for 6 hours at 0.7 atm, 20°C, and initial RH of 70% in either airtight or non-airtight containers with an air-flow rate of 0.415 L.s-1, plus airtight and non-airtight 1.0 atm controls. After the flight simulation, the fruit were transferred to 1.0 atm cold rooms at 20°C and 70% RH or 7°C and 90% RH for 7 days. The VPD was monitored during flight simulation and weight loss was evaluated after harvest, after 6 h (flight simulation), and daily for 7 days. Exposure of cucumbers to 0.7 atm in either airtight or non-airtight containers increased moisture loss compared with that at 1 atm. The VPD was higher in non-airtight containers, and enhanced transpiration, leading to greater moisture loss during the simulated air shipment as well as throughout the storage period. The atmosphere in airtight conditions was quickly water-saturated, limiting transpiration rate and moisture loss during the air shipment simulation. Loss of moisture from the cucumbers exposed to 0.7 atm in airtight containers was greater throughout the storage period compared with fruit in 1.0 atm airtight containers. These latter results suggest that low P during air transport may induce physiological stresses on cucumbers, especially in the water diffusion pathway though the epidermis. | |
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