Blue LED alleviates chilling injury in cucumber (Cucumis sativus L.) fruits via membrane lipid metabolism regulation

As a cold-sensitive vegetable, cucumber is susceptible to chilling injury (CI) during low-temperature storage and cold chain transport. The aim of this study was to investigate the possible impacts of blue LED treatment on cucumbers stored in low-temperature conditions. The results showed that the malondialdehyde (MDA) content and the relative electrolyte leakage rate of cucumbers were significantly reduced by blue LED compared to untreated group, meanwhile the ultrastructural integrity of cucumbers peel cells, including the cell membranes and the structures of organelles, was effectively maintained. Furthermore, the treatment notably increased the expression levels of genes related to fatty acid desaturation (FAD) while suppressing the activities of key enzymes associated with fatty acid hydrolysis. This led to increased content of phospholipids and unsaturated fatty acids (USFA), which resisted the destruction of cellular membrane structure by low-temperature stress. Additionally, the treatment significantly activated the ascorbic acid–glutathione (AsA–GSH) cycle in cucumbers, which enhanced the antioxidant capacity and reduced the oxidative damage of cell membranes. These findings show that blue LED can effectively mitigated the development of chilling injury in cucumbers, suggesting its potential as a new solution to maintain the quality during low-temperature storage. • Blue LED treatment mitigated the development of chilling injury in cucumber. • Blue LED maintained the integrity of cucumber peel subcellular structure. • Oxidative damage in cucumber was attenuated by Blue LED treatment. • The accumulation of unsaturated fatty acids and phospholipids was promoted. • Cold tolerance was enhanced by inhibiting lipid peroxidation and maintaining membrane fluidity.