Structural membrane alterations in tropical horticultural crops under postharvest chilling stress

Optimal storage temperatures are essential for preserving vegetables' quality. Tropical plants, meanwhile, have a significant vulnerability to low temperatures, yet the majority of vegetables are farmed within tropical climates. Low temperatures can cause oxidative stress in vegetables, resulting in a condition known as 'chilling injury' (CI). The symptoms may manifest as visible external traits, including color shading, surface pitting, surface browning, and water soaking. Conversely, CI can alter internal changes such as water succulence, internal browning, and flesh translucence. Additionally, CI potentially triggers abnormal metabolic processes, resulting in atypical ripening or the development of an unpleasant odor. Reactive oxygen species (ROS) that occur during oxidative stress at low temperatures first harm the membrane of organelles and subsequently damage macromolecules like proteins, lipids, and DNA/RNA. Therefore, visual signs of cellular damage indicate the advanced stage of damage after membrane transition. The tolerant plant generally contains more polyunsaturated fatty acids (PUFA) than monounsaturated fatty acids (MUFA) in its cellular membrane. All damaging cells display an imbalance between ROS and the scavenging systems, including chemical compounds and enzymatic cycles. Inducing antioxidant systems is essential for preserving the quality of chilled vegetables. Therefore, when the cells reach the advanced stages of CI development, specifically after membrane leakage, they are unable to recover and will progress to the final stage of CI, exhibiting phenotypic CI symptoms.