Exogenous trisodium phosphate inhibits pericarp browning of harvested longan fruit through enhancing phenylpropanoid metabolism

Postharvest longan fruits are highly vulnerable to pericarp browning, greatly reducing their market value and shelf life. As a key pathway for plant stress resistance, phenylpropanoid metabolism is closely associated with pericarp browning. The research focused on the regulatory effects of exogenous sodium phosphate (TSP) treatment on the phenylpropanoid metabolic pathway in postharvest longan fruits, elucidating the physiological mechanisms through which it suppresses pericarp browning by activating defense-related metabolism. The findings indicated that 0.5 g L -1 TSP elevated the activities of pivotal enzymes in phenylpropanoid pathways within longan pericarp. TSP treatment enhanced the production of beneficial phenolic compounds, while effectively suppressing the activities of peroxidase (POD) and polyphenol oxidase (PPO). Consequently, the progression of pericarp browning was delayed, thereby preserving fruit postharvest quality. This work established a theoretical basis for innovative phosphate-based longan preservation technologies.