Quality of Red Sweet Pepper Fruit Treated with 1-MCP during a Simulated Post-harvest Handling Chain

Red pepper fruit (Capsicum annuum L. cv Setubal) were treated with air (control) or 900 ppb 1-methylcyclopropene (1-MCP) for 24 h at 20°C. The fruit were packed in perforated polypropylene and stored for 4.5 days at 8°C (storage), 3 days at 20°C (simulated retail display), and 4.5 days in domestic refrigerator at 5.6°C. Fruit stored continuously at 20°C served as reference of respiration rate and ethylene production. The fruit quality, storage disorders, and physiological behavior in this simplified post-harvest handling chain and the possible effects of the CO₂ accumulated during 1-MCP treatments were particularly studied. The critical points of the simulated post-harvest chain as regards fruit quality were the retail display stage at 20°C, the inhibition of ethylene as a side effect of 1-MCP, and, to a lesser extent the domestic refrigeration phase. Simulated retail display exacerbated shriveling and weight loss, and negatively affected aroma, finger texture and, to a lesser extent, fruit taste, and mouth texture. The 3% increase in the CO₂ accumulated in both treatments resulted in a transient increase in the respiration rate, flesh and juice hue angle, glutamic and ascorbic acids; an increase in succinic acid (higher in 1-MCP treated fruit), and a transient decrease in citric acid, juice lightness and chroma. Compared with the control, the 1-MCP prevented the increase in skin chroma during the storage phase, the upsurge of ethylene production during the retail display phase, and doubled the fumaric acid levels in the refrigerator phase. 1-MCP may have increased the fruit susceptibility to shriveling and weight loss and, to a greater extent, pitting and gray mold rot in the domestic refrigerator. In brief, 1-MCP cannot be recommended for extending non-climacteric pepper shelf-life.