A novel, facile, low-cost, energy-free magnetic field device for regulating energy levels and its application in the cold storage and shelf of edible-window-period kiwifruit

• A novel, facile, low-cost, easy-to-fabricate, energy-free magnetic field preservation device was designed and fabricated, which has the potential to promote the development of green food. • The magnetic field treatment device, which combined sintered ferrite and plastic baskets, effectively maintained the storage and shelf quality of edible-window-period kiwifruit, achieving comparable preservation effects to 1-MCP treatment. • The study elucidates the regulatory mechanisms of energy status in edible-window-period kiwifruit under appropriate magnetic field conditions. Reducing energy consumption is crucial for advancing green agriculture. This study developed a novel, low-cost, energy-free magnetic preservation device to extend the storage and shelf life of edible-window-stage kiwifruit. The effects of different magnetic field strengths (3, 9, and 15 mT) were evaluated, with 1-MCP (0.5 µL/L) and untreated fruit (CK) as controls. Fruits were stored at 4 °C for 12 days, followed by 7 days at 25 °C. Results showed that 3 mT treatment achieved preservation efficacy comparable to 1-MCP, significantly reducing decay rate, ΔE value, soluble solids content, respiration intensity, and ethylene production while maintaining higher firmness and titratable acidity. At the end of shelf storage, 3 mT-treated fruit exhibited 18.15 %, 67.07 %, and 128.17 % higher exocarp, mesocarp, and core firmness, respectively, versus CK, while decay rates were 5.8 % lower than CK—outperforming 1-MCP. Additionally, the magnetic field maintained higher activities of energy metabolism-related enzymes (SDH, CCO, H + -ATPase, Ca 2+ -ATPase, G6PDH and 6PDGH), leading to higher ATP and ADP contents, EC levels, and lower AMP content compared to the CK. Transcriptomic analysis suggested that 3 mT may sustain the expression of energy metabolism enzyme-related genes, thereby maintaining higher energy metabolism levels and preserving the quality of kiwifruit during 4 °C storage and 25 °C shelf life. Conversely, 15 mT was found to accelerate quality deterioration by regulating the expression of energy metabolism-related genes and inhibiting enzyme activities. This study demonstrates that optimal magnetic field treatment (3 mT) effectively preserves postharvest kiwifruit quality by regulating energy metabolism, offering a sustainable alternative to chemical treatments. In this study, we developed a novel, facile, low-cost magnetic field device, which overcomes the disadvantages of traditional magnetic field preservation devices such as high energy consumption, high cost, and limited magnetic field range. The research investigated the effects of different magnetic field strengths on the physiological quality of edible-window-period kiwifruit and deeply analyzed the mechanism of magnetic field preservation from the perspective of energy metabolism. The results revealed that the appropriate magnetic field strength (3 mT) maintained the quality of edible-window-period kiwifruit by regulating the activities of energy metabolism-related enzymes and the expression of related genes.