High-voltage cold plasma alleviates chilling injury in green pepper by synergistically regulating antioxidant ane membrane lipid metabolism

Green pepper ( Capsicum annuum L.) is prone to chilling injury (CI) during cold storage at 4℃, leading to rapid quality deterioration. Existing preservation technologies have limitations such as chemical residues and thermal damage. This study was the first to investigate the alleviating effect and physiological basis of high-voltage cold plasma (HVCP) on postharvest CI in green pepper. Fruits were treated with HVCP (50 kV) for 30–150 s and then stored at 4℃ for 12 days. The results showed that the 60 s treatment achieved the optimal effect, reducing the CI index by 94.74% and weight loss rate by 73.54%, and significantly delaying the deterioration of texture, color and chlorophyll content. Mechanistic analysis revealed that HVCP induced an early, transient and reversible moderate accumulation of reactive oxygen species (ROS) H₂O₂ and O₂⁻ contents increased by 15.59% and 89.82%, respectively, compared with the control on day 2 after treatment), and synergistically activated the antioxidant enzyme system and the ascorbate-glutathione (AsA-GSH) cycle at the transcriptional level. Meanwhile, it inhibited the activities and gene expression of key enzymes involved in membrane lipid degradation, reduced phospholipid degradation and polyunsaturated fatty acid oxidation, and increased the unsaturation degree of fatty acids (U/S ratio) by 22.17% at the end of storage compared with the control, thereby maintaining cell membrane integrity. Correlation and principal component analyses confirmed that HVCP enhanced the chilling tolerance of green pepper by coordinately regulating antioxidant defense and membrane lipid homeostasis, providing experimental evidence for its application as a green non-thermal preservation technology.