Antioxidant capacity is one of the most important biological activities in fruits and vegetables and is closely related to human health. In this study, ‘Eureka’ lemons were used as experimental materials and stored at 7–8 °C MT (melatonin, 200 μmol, soaked for 15 min) and CA (controlled atmosphere, 2–3% O₂ + 15–16% CO₂) individually or in combination for 30 d. The changes in lemon fruits’ basic physicochemical properties, enzyme activities, and antioxidant capacities were studied. Comparing the combined treatment to the control, the outcomes demonstrated a significant reduction in weight loss, firmness, stomatal opening, and inhibition of polyphenol oxidase (PPO) and peroxidase (POD) activities. Additionally, the combined treatment maintained high levels of titratable acidity (TA), vitamin C (VC), total phenolic content (TPC), and antioxidant capacity and preserved the lemon aroma. Meanwhile, the correlation between fruit color, aroma compounds, and antioxidant capacity was revealed, providing valuable insights into the postharvest preservation of lemons. In conclusion, the combined treatment (MT + CA) was effective in maintaining the quality and antioxidant capacity of lemons.

The color and aroma of nectarines experience adverse effects from cutting, resulting in the fast senescence of fruit tissue. Therefore, 1-methylcyclopropene (1-MCP) was used to treat postharvest nectarines before cutting, and its effect on the surface browning and aroma alteration were investigated. The results indicated that 1-MCP restrained the soluble quinone (SQC) accumulation in fresh-cut nectarines by regulating the peroxidase (POD) and polyphenol oxidase (PPO) activities and the metabolism of phenolic compounds. Compared with the control, 1-MCP pre-cutting treatment maintained the ultrastructural integrity of the cell wall in fresh-cut nectarines, which also showed reduced malondialdehyde (MDA) content and reactive oxygen species (ROS) and enhanced the 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) radical scavenging activities. Electronic nose and GC-MS analysis revealed that the aroma profiles presented significant differences in the control and 1-MCP treatment during the storage at 0 °C for 10 days. The browning value of the 1-MCP pre-cutting treatment was 29.95% lower than the control, which prevented the loss of aroma on day 10. The fresh-cut nectarines could still maintain the characteristic flavor, while the flesh maintains its firmness. The 1-MCP pre-cutting treatment improves the sensory and aroma characteristics of fresh-cut fruits, which is beneficial to the preservation of fresh-cut fruits, improves transportation efficiency, and then improves the overall quality and market attractiveness of the fruit.