Effect of 1-Methylcyclopropene Combined with Ethylene Absorbent on Softening and Shrinking of Passion Fruits

To investigate the effect of 1-methylcyclopropene (1-MCP) combined with ethylene absorbent on postharvest softening and shrinking in passion fruits, ‘Qinmi 9’ golden passion fruits treated with 1-MCP alone or combined with ethylene absorbent were analyzed for quality parameters, cell wall metabolism, and membrane lipid metabolism indicators. The results showed that compared with the untreated control group, 1-MCP treatment effectively delayed the progression of softening and shrinking, thereby maintaining fruit quality. The combined treatment suppressed respiration intensity and delayed the onset of respiration peaks. This treatment slowed the decline of hardness and peel moisture content, reduced the shrinkage index, maintained cell wall integrity, effectively delayed the degradation of protopectin and cellulose, and inhibited the accumulation of soluble pectin. It significantly reduced the activities of pectin methylesterase (PME), polygalacturonase (PG), and exocellobiohydrolase (CX), while concurrently mitigating membrane lipid peroxidation and reducing cell membrane permeability and malondialdehyde (MDA) content. Correlation analysis indicated that the shrinkage index exhibited highly significant positive correlations with respiration intensity, soluble pectin content and PME activity (P < 0.01), and highly significant negative correlations with peel moisture content and protopectin content (P < 0.01). In summary, 1-MCP combined with ethylene absorbent delayed fruit softening and shrinking by synergistically regulating the activity of cell wall degradation enzymes and membrane lipid metabolism in passion fruits, extending the shelf life by 4-6 days. This finding provides a theoretical basis for developing preservation techniques for golden passion fruits stored at ambient temperature.