Quality deterioration characteristics and metabolomic analysis of nano-packaged Venus Golden apples under dynamic...

Temperature fluctuations are a major cause of apple quality deterioration during distribution, but their effects on nano-packaging performance and fruit metabolism remain unclear. Long-term cold-stored Venus Golden apples (VG) were evaluated using quality, physiological, and untargeted metabolomic analyses. Different packaging treatments were compared, and NPF-packaged fruit was stored at constant 10 °C, constant 20 °C, or fluctuating 10-20 °C. NPF effectively delayed changes in color, texture, sugars, organic acids, and antioxidant capacity. However, temperature fluctuations weakened its preservation efficacy and intensified browning, softening, and oxidative damage. Metabolomic analysis revealed disturbances in alanine, aspartate and glutamate metabolism, galactose metabolism, and arginine biosynthesis, accompanied by accelerated depletion of sugars, organic acids, and amino acids. Nine candidate biomarkers of quality deterioration, including L-glutamic acid, γ-aminobutyric acid, and D-sorbitol, were identified. These findings provide insights for cold-chain temperature management, nano-packaging optimization, and metabolite-based quality monitoring.