Shelf life extension of fresh lotus pods and seeds (Nelumbo nucifera Gaertn.) in response to treatments with 1-MCP and lacquer wax

Lotus pods were treated with 0.5 μL L−1 of 1-methylcyclopropene (1-MCP) and 3% lacquer wax and then stored at 25 ± 1 °C and 90%-95% relative humidity to investigate their effects alone and in combination on browning and postharvest quality during 8 d of shelf life. Respiration rate, firmness, reactive oxygen species (superoxide anion (O2−) production rate and H2O2 concentration), malondialdehyde (MDA) and total phenol concentrations, and the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO) were evaluated. 1-MCP or lacquer wax reduced browning and retained the quality of lotus pods and seeds. However, lacquer wax had little influence on the respiration rate, and 1-MCP-treated pods were firmer than untreated pods for only 6 d. The combination treatment of lacquer wax followed by 1-MCP treatment showed equivalent effects on respiration rate and firmness to lacquer wax alone. However, the lotus pods that were treated with 1-MCP first, and then coated with lacquer wax, had better retention of firmness and total phenol concentration, reduced respiration rate, O2− production rate, accumulation of H2O2 and MDA, and browning degree, increased SOD and CAT activities, and decreased PPO and POD activities when compared with those in other treatments. Compared with controls, 1-MCP treatment followed by lacquer wax coating treatment also delayed cell wall degradation, plasmolysis, and preserved cellular integrity of lotus seeds. These results indicate combination treatment provided an effective method to delay the postharvest senescence of fresh lotus pods and seeds.