The Influence of Storage Conditions and 1-MCP Treatment on Ethylene Evolution and Fruit Quality in ‘Gala’ Apples

The effect of storage conditions and 1-MCP treatment on ethylene production and quality of ‘Gala’ apples stored in normal and controlled atmosphere conditions was evaluated during two successive seasons, 2001/2002 and 2002/2003. Apples were harvested in a commercial stage and cooled down to a temperature of 1°C. After that there were treated with 1-MCP in a concentration of 0.625 μl·L^-1 for 24 hours. Treated and untreated (control) apples were stored for 120 and 180 days in the cold storage rooms at 2±0.5°C under normal atmosphere (NA) conditions or controlled atmosphere (CA) with 2% O₂ and 2% CO₂. Directly after storage and after shelf life (additionally 7 days at 18°C) internal ethylene concentration (IEC) and activity of ACC oxidase were determined. The following quality parameters were recorded as well: flesh firmness (FF), total soluble solids (TSS), and titratable acidity (TA).

Application of 1-MCP after harvest strongly inhibited ACC oxidase in apples following storage in air or controlled atmosphere for 120 and 180 days. This inhibition was also noted after 7 days of shelf life. There was no reduction in ACC oxidase activity of CA stored apples in comparison to NA stored, but the IEC directly after storage was lower for fruits stored in CA conditions than for fruits stored in NA. Internal ethylene concentration was significantly lower for the 1-MCP treated fruits, both directly after storage in NA or CA and after shelf life. The application of 1-MCP delayed softening and loss of titratable acidity in ‘Gala’ apples stored in NA and CA conditions. There was no clear effect of 1-MCP treatment on total soluble solids content in stored ‘Gala’ apples