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

Green pepper ( Capsicum annuum L.) is prone to chilling injury (CI) during cold storage at 4 °C, causing quality deterioration. This study investigated the alleviating effect and physiological basis of high-voltage cold plasma (HVCP) on postharvest CI in green pepper. Fruits were treated with HVCP at 50 kV for 30–150 s and stored at 4 °C for 12 days. The 50 kV/60 s condition was most favorable, reducing the CI index by 94.74% and weight loss by 73.54%, while delaying deterioration of texture, color, and chlorophyll content. 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. It also activated the antioxidant enzyme system and ascorbate-glutathione (AsA-GSH) cycle at the transcriptional level, inhibited key enzymes involved in membrane lipid degradation, reduced phospholipid degradation and polyunsaturated fatty acid oxidation, and increased fatty acid unsaturation (U/S ratio) by 22.17% at the end of storage. Correlation and principal component analyses confirmed that HVCP enhanced chilling tolerance by coordinately regulating antioxidant defense and membrane lipid homeostasis, supporting its potential as a green non-thermal preservation technology.