1-MCP and high-CO₂ treatments modulate flavor metabolic responses to post-storage short-term warming in ‘Madoka’ peach

Abstract

Although postharvest storage is conducted under controlled temperature conditions, fruit often experiences short-term warming during handling and distribution, potentially affecting ripening and flavor metabolism. This study investigated the effects of short-term warming on flavor-related physiological and biochemical responses in ‘Madoka’ peach (Prunus persica L.) subjected to commercial pre-storage treatments (1-MCP and high CO₂). Fruit were treated with 1 μL l^-1 1-MCP for 12 h or with 30% CO₂ for 6 h in a sealed 62 L container at 20 °C, and then stored at 10 °C and 85% relative humidity for 12 days. After storage, fruit were analyzed either immediately (10 °C flesh temperature) or after short-term warming to a flesh temperature of 20 °C. Post-storage short-term warming did not significantly affect soluble solids content, titratable acidity, malic acid content, firmness, or polygalacturonase activity regardless of pre-storage treatment. In contrast, short-term warming enhanced ethylene production and respiration in control fruit, whereas these responses were largely suppressed by 1-MCP and CO₂ treatment. Sucrose content remained stable, while changes in glucose and fructose were limited to control fruit during early storage and were attenuated by 1-MCP or delayed by CO₂ treatment. Short-term warming also affected volatile profiles in a treatment-dependent manner, with the magnitude and direction of responses varying among individual compounds and volatile classes. Consistent with these physiological changes, warming differentially regulated the expression of genes associated with volatile biosynthesis, whereas transcriptional responses of sugar metabolism-related genes were generally gene-dependent and less pronounced. These findings demonstrate that flavor-related metabolism responds rapidly to post-storage short-term warming before detectable changes in conventional fruit quality occur, and that commercial pre-storage treatments differentially regulate this metabolic responsiveness.