Location: Physiology and Pathology of Tree Fruits Research
Project Number: 2094-43000-008-021-T
Project Type: Trust Fund Cooperative Agreement
Start Date: May 1, 2022
End Date: Sep 30, 2025
Objective:
1. Identify temperature/atmospheric combinations that reduce superficial scald without causing other disorders.
2. Determine what post-storage ripening and scald controls can be used following ULO CA.
3. Evaluate tests that indicate disorder control effectiveness of ULO CA.
Approach:
Controlled atmosphere using less than 1% O2 controls pear ripening and some peel disorders. Rapidly applied (pull down beginning less than a week after placement in storage) CA storage is the only effective ripening and superficial scald control protocol currently acceptable for organically produced apples and pears. A roadblock to widespread use of ULO-CA to store d’Anjou pears is the risk of developing other disorders including black speck and internal browning or pithy brown core. Furthermore, scald can develop when post-storage cold chains last a month or more. ULO CA storage parameters that reduce black speck, internal disorder, and superficial scald risk without compromising ripening control or eating quality would remove an important barrier to safe, effective use of existing ULO CA technology. To accomplish this goal, we will test techniques we have collectively developed for apples and pears to overcome these and similar issues. We have found that storing pears at warmer temperatures following 1-MCP treatment, which has a similar impact on ripening as ULO CA, is a safe and effective way to provide fully ripe fruit to the consumer and may help reduce internal browning risk caused by this stress combination. We have evidence of and will test whether black speck may arise from combinations of ULO, high CO2, and condensation on the fruit surface. Finally, our work with apple shows that fruit stored in ULO CA following can be treated with 1-MCP after storage and, with pear, indicates delayed treatment of up to 3 months with the new squalane superficial scald control drench can reduce or eliminate superficial scald if ULO CA was soon after placed in storage. We can monitor natural peel chemicals that may indicate whether the CA and room settings are controlling the disorders.
