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United States Department of Agriculture

Agricultural Research Service

Research Project: Epicuticular changes in response to ethylene regulation in apple
2010 Annual Report


1a.Objectives (from AD-416)
Determine interrelationship between controlled atmosphere (CA), relative humidity (RH), and SmartFresh (MCP) on apple cuticle structure, function and disorder.


1b.Approach (from AD-416)
Previously, work done at the ARS laboratory in Wenatchee indicated preharvest treatments that increased ethylene production in ‘Granny Smith’ apples also increased fruit epicuticular wax production during storage. Similarly, treatments that reduced postharvest ethylene production were associated with a delay in fruit epicuticular wax production during storage.

Ethylene is implicated in apple epicuticular wax production. Wax production is necessary for “healing” the microcracking associated with normal fruit growth and cuticle expansion. Degree of microcracking “healing” by the time storage conditions are achieved influences fruit cuticle water vapor permeance, which, together with ambient conditions, establishes desiccation potential of fruit in storage. Moisture loss of fruit in storage followed by rewetting during water-based fruit processing may be implicated in cuticle cracking around lenticels, and disorders associated therewith.

This project will focus on the interrelationship of fruit ethylene production, fruit cuticle water vapor permeance and ambient water vapor pressure during storage and the impact these have on physiological storage disorders. Documents Trust with Agrofresh. Log 37327.


3.Progress Report

This project relates to objective 3 of the associated in-house project which seeks to identify factors that influence postharvest fruit quality and development of market-limiting physiological disorders. Experiments were conducted to examine the effect of relative humidity (RH) and modified atmosphere storage on moisture loss (shrivel) of fruit with or without prestorage treatment with SmartFresh (1-MCP). ‘Golden Delicious’ apples were treated 24 h after harvest with 1-MCP (controls ripening) and placed in controlled atmosphere (CA) or regular atmosphere (RA) storage at 33 °F for 8 months. RH was maintained at either 90% or 100%. At 90% humidity, all fruit showed signs of shrivel regardless of CA or RA storage, whereas at 100% RH none of the fruit showed these symptoms. There was no treatment effect from 1-MCP on fruit shrivel. As an indicator of ripening, we also measured peel color. Fruit treated with 1-MCP were the least ripe (greenest) when stored at 100% RH under CA conditions, followed by those stored at 100% RH under RA conditions. At 90% RH in RA storage, fruit treated with 1-MCP were no different than untreated fruit. From this study, it is very apparent that RH affects fruit moisture loss as well as ripening under certain conditions.

Progress is monitored through periodic meetings as well as annual written progress reports to the funding organization.


Last Modified: 11/25/2014
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