Dynamic Control of Atmosphere and Temperature Based on Fruit CO2 Production: Practical Application in Apple Storage and Effects on Metabolism, Quality, and Volatile Profiles

This study assessed the potential of a novel two-factor dynamic storage system DCA-CD Plus, which allows estimation of the oxygen partial pressures and room temperatures for optimum fruit conservation, based on monitoring fruit CO2 production. This was achieved for the apple cultivars "Jonagold," "Pinova," and "Red Prince" by a comparison with established postharvest strategies such as storage under regular atmosphere (RA) or static controlled atmosphere (CA), while also incorporating the effects of the ethylene inhibitor 1-methylcyclopropene (1-MCP). In contrast to other dynamic controlled atmosphere (DCA) systems, DCA-CD Plus requires no additional installation of technology in the storage facility and does not rely on a small sample size to estimate the optimum storage conditions. DCA-CD Plus allowed storing different apple cultivars together, a considerable advantage for commercial practice. Storage under DCA-CD Plus slowed down the fruit respiration rate and suppressed ethylene synthesis, consequently providing a greater maintenance of firmness (FF) and titratable acidity (TA) when compared to RA or CA storage. Variable setting of storage temperatures reduced the energy consumption of cooling equipment without negatively affecting fruit quality conservation. CA storage and 1-MCP applications suppressed the formation of aroma in the stored apples, while DCA-CD could safely induce anaerobic metabolism, thus increasing the substrate availability for the synthesis of aroma compounds.