UV irradiation combined with high voltage electrostatic field alleviates surface discoloration in fresh-cut purple yam by regulating enzymatic browning.

Fresh-cut purple yam is highly susceptible to enzymatic browning during storage, primarily driven by peroxidase (POD), while superoxide dismutase (SOD) serves as an oxidative-stress marker. This study investigated the effects of ultraviolet-C (UV-C), high-voltage electrostatic field (HVEF), and their combination (UV-HVEF) on browning inhibition and quality preservation. The combined treatment (UV-C at 68 W for 120 min followed by HVEF at 30 kV for 8 min) exhibited the strongest synergistic effect, achieving the highest L* value, total phenolics, flavonoids, and anthocyanins, along with the lowest browning degree after 8 days of storage. UV-HVEF induced tryptophan exposure and α-helix loss in these enzymes, leading to inactivation, while downregulating POD, phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H) expression and preserving p-coumaric acid at 54.56% higher than the control. Correlation analysis confirmed brightness positively correlated with phenolics and negatively with enzyme activities. Scanning electron microscopy revealed HVEF damaged starch granules, while UV-HVEF caused irregular morphology. Overall, UV-HVEF is an effective non-thermal strategy balancing enzyme inactivation with quality maintenance.