Static magnetic field combined with controlled atmosphere delays browning and preserves quality of postharvest litchi

Pericarp browning is a key cause of postharvest quality deterioration in litchi fruit. This study investigated the effects of a static magnetic field (SMF) combined with controlled atmosphere (CA) storage on browning control and quality preservation. Litchi fruit were exposed to a 5 mT SMF for 120 min before storage, followed by CA conditions (5% O₂, 5% CO₂, and 90% N₂). After 12 d of storage, CA + SMF-5 reduced the browning index from 3.9 to 2.6 and decay incidence from 90% to 21%, while maintaining higher firmness (10.1 vs. 8.4 N) and anthocyanin content (0.82 vs. 0.43 g kg⁻¹) than the control. Lower reactive oxygen species accumulation and membrane damage were observed together with reduced polyphenol oxidase, peroxidase, and lipoxygenase activities. In addition, CA + SMF-5 suppressed LcPPO and LcANR expression while maintaining higher LcUFGT expression. These findings suggest that CA + SMF-5 delays browning and improves postharvest quality by regulating membrane stability and phenylpropanoid metabolism. This study provides a potential non-chemical strategy for improving postharvest preservation of litchi fruit.