Effect of 1-MCP Combined with ε-polylysine Atomization on Active Oxygen and Phenylpropane Metabolism in Winter Jujube

To investigate the preservation effect of 1-methylcyclopropene (1-MCP) combined with ε-poly-L-lysine (ε-PL) on the postharvest quality of winter Jujubes. 'Zhandong No.2' Jujube fruits were used as raw materials. .The Winter Jujube were treated with 1 µL/L 1-MCP alone and in combination with 0.5 g/L ε-PL, all fruits were stored at 0 ℃, and samples were taken for analysis on days 0, 22, 44, 66, and 88 of storage to study the effect on sensory quality, sugar metabolism, reactive oxygen species (ROS) and phenylpropanoid metabolism. Compared with the control group (CK), the results showed that the 1-MCP and 1-MCP+ε-PL treatments effectively delayed the progression of reddening and decay, thereby stabilising the storage quality. The 1µL/L 1-MCP+0.5 g/L ε-PL treatment further reduced the reddening rate, and no rot was observed during storage. 1-MCP+ε-PL significantly inhibited the consumption of soluble solids content (SSC) and sucrose, inhibited the accumulation of fructose and glucose, delayed the increase of superoxide anion (O₂·^-), hydrogen peroxide (H₂O₂), and malondialdehyde (MDA), increased the activities of superoxide dismutase (SOD) and catalase (CAT), maintained the activities of phenylpropanoid metabolism-related enzymes, such as phenylalanine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), and 4-coumarate CoA ligase (4CL), and the contents of secondary metabolites, including total phenolic, flavonoids, and lignin. The above results showed that 1-MCP combined with ε-PL effectively maintained the storage quality of winter Jujube by regulating the activities of antioxidant and phenylpropanoid metabolism-related enzymes, and related metabolites.