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United States Department of Agriculture

Agricultural Research Service

Research Project: Epicuticular changes in response to ethylene regulation in apple
2009 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 1 of the associated in-house project which seeks to identify factors that influence postharvest fruit quality and development of market limiting physiological disorders. Several preliminary experiments were conducted to examine the effect of storage humidity on quality of fruit with and without prestorage treatment with 1-MCP. In one experiment, ‘Gala’ apples were treated immediately after harvest by dipping fruit for 2 minutes in increasing rates of EpiShield--a natural wax formulation. At 1.5-3% this aqueous formulation helps seal the microcracks in the fruit peel that have developed as a normal function of fruit growth. Treatment with EpiShield was followed by treatment with 1-MCP and storage for 8 months at 33°F. Apples treated with EpiShield plus 1-MCP showed reduced LB potential compared with fruit treated only with 1-MCP.

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


Last Modified: 9/20/2014
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