Effects of DPA, 1-MCP, and CO₂ Concentration on External CO₂ Injury of ‘Empire’ Apples

The following article is based on work done by F. Razafimbelo, J.F. Nock, and C.B. Watkins at Cornell University, New York (2006, HortScience 41(4):978)

The susceptibility of ‘Empire’ apples to external CO₂ injury during controlled atmosphere (CA) storage is substantially increased with 1-MCP treatment (DeEll et al., 2003). This physiological disorder is characterized by bronze, rough, sunken well-defined lesions in the skin.

Razafimbelo et al. (2006) investigated the effects of 1-MCP on external CO₂ injury of ‘Empire’ apple using several approaches:

1. Fruit were treated with 1%, 2.5%, or 5% CO₂ during storage. Higher injury levels were associated with exposure to higher CO₂ concentrations.
2. Fruit were exposed to 2.5% or 5% CO₂ for 3-week periods throughout storage, with CO₂ otherwise kept at 1%. Most injury occurred in fruit treated with elevated CO₂ during the first 3 weeks of storage, and 1-MCP did not extend the period of susceptibility to injury.
3. Exposure of fruit to CA with 5% CO₂ after harvest was delayed for up to 14 days. Susceptibility to injury remained high during the delay in 1-MCP-treated fruit in contrast to untreated fruit.
4. Fruit were treated with 250, 500, or 1000 ppm of diphenylamine (DPA). DPA eliminated injury in 1-MCP treated fruit, even at concentrations of 250 ppm.

This data confirms that 1-MCP increases susceptibility of ‘Empire’ apples to external CO₂ injury and extra care is therefore required to avoid fruit losses. Only DPA application has been shown to eliminate the risk of injury.