Regulation of nectarine flesh browning through pre-harvest application of chitosan coatings

• Pre-harvest 1.5 g/L chitosan (4 sprays, 7-day interval) inhibits nectarine flesh browning in cold storage and preserves quality. • Pre-harvest chitosan acts via multi-pathway synergy: maintaining energy, stabilizing cells, slowing cell wall degradation, balancing sugar metabolism, boosting ROS scavenging. • This study offers a safe, eco-friendly nectarine cold storage method for industry sustainability. Nectarine ( Prunus persica L.) is a popular economic fruit, but flesh browning during low-temperature cold storage severely limits its storage period and commercial value, with existing studies on pre-harvest chitosan treatment focusing on single metabolic pathways. This study explored the regulatory effect and mechanism of pre-harvest 1.5 g/L chitosan spraying (4 times, 7-day interval) combined with (0±0.5)°C cold storage on 'Zhongyou No.4′ nectarine browning. Results showed the treatment delayed browning onset from week 2 to 3, reduced browning index, and maintained fruit quality. Mechanistically, it synergistically regulated multiple metabolic pathways: preserving mitochondrial function for energy supply, balancing mineral elements (K, Ca, B) to stabilize cell structure, inhibiting cell wall-degrading enzymes, maintaining sucrose-hexose balance, and enhancing ROS scavenging capacity. This work fills the gap of multi-metabolic network regulation research, providing a safe and effective technical and theoretical basis for nectarine cold storage preservation.