Elevated CO2 in dynamic controlled atmosphere storage: Impact on anaerobic metabolism and overall quality of 'Maxi Gala' apples.

Background: The present study investigated the effects of high CO₂ partial pressures (pCO₂) in dynamic controlled atmosphere monitored by respiratory quotient (DCA-RQ 1.3) on the anaerobic metabolism compounds, physiological disorders and overall quality of 'Maxi Gala' apples after 9 months of storage (2.0 °C), plus 7 days of shelf life (20 °C). Two experiments were conducted over 2 years. In the first year, 'Maxi Gala' apples were stored under controlled atmosphere (CA - 1.2 kPa O₂ + 2.0 kPa CO₂), CA + 1-methylcyclopropene (1-MCP), DCA by chlorophyll fluorescence (DCA-CF + 1.2 kPa CO₂) and DCA-RQ 1.3 with different pCO₂ (0.4, 1.2, and 1.6). The same treatments were evaluated in the second year, with addition of DCA-RQ 1.3 + 2.0 kPa CO₂.

Results: 'Maxi Gala' apple stored under DCA-RQ 1.3 + 0.4 kPa CO₂ and DCA-CF maintained healthy fruit amount similar to DCA-RQ 1.3 + 1.2 and 1.6 kPa CO₂, but with lower flesh firmness. DCA-RQ 1.3 with higher pCO₂ (1.6 or 2.0) increases the production of ethyl acetate, but did not impact physiological disorders compared to DCA-CF. CA + 1-MCP maintained high flesh firmness, but reduced healthy fruit amount.

Conclusion: The present study has demonstrated that DCA-RQ 1.3 with 1.6 or 2.0 pCO₂ can be adopted for 'Maxi Gala' apples storage, resulting in similar or better fruit quality than DCA-RQ 1.3 + 1.2 kPa CO₂. Additionally, the adoption of high pCO₂ in the DCA-RQ storage system can result in cost reductions related to CO₂ adsorption. © 2024 Society of Chemical Industry.