Effect of hot water treatment on chilling injury and lignification of cold-stored fresh areca nut ( L.).

Fresh areca nut is widely favored by consumers in South and Southeast Asia. However, postharvest areca nut perished quickly and was vulnerable to chilling injury (CI) and lignification during traditional cold storage. In order to alleviate this situation, hot water treatment was applied to investigate its effect on CI and lignification of fresh areca nut during cold storage at 13 °C. Areca nuts were submersed in hot water at 45 °C (HW45) and 50 °C (HW50) for short-term 5 min compared to fruit submersed in water at 20 °C (CT), then stored at 13 °C with 90% humidity for 60 days. CI, malondialdehyde (MDA), electrolyte leakage (EL), lignin and total phenolic content, related enzymes including phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase activity (POD) were examined. Results indicated that two HW treatments both induced chilling tolerance and delayed lignification of areca nut to varying degrees during cold storage compared with the CT. Among which, HW45 treated-areca nuts had the lowest CI, MDA content and EL while maintaining the highest total phenolic content. Moreover, no significant effects were found between HW45 and HW50 on tissue lignification, but they both effectively blocked lignin accumulation by inhibiting PAL, CAD and POD activities compared with the CT. The present study provided a safe physical method to mitigate CI and delay tissue lignification in cold-stored areca nut.