Mechanisms underlying the effect of high-temperature curing treatments on the browning response of fresh-cut yams

Fresh-cut yams are prone to browning, which impacts their quality and marketability. This study evaluated the efficacy of a high-temperature curing (HTC) treatment (35 degrees C for 7 days) in inhibiting the postharvest browning of fresh-cut yams. Results indicated that the HTC treatment primarily mitigated browning by inhibiting key enzymes involved in phenolic oxidation, including polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL), while reducing the accumulation of total phenolics and lignin. HTC also reduced respiration rate and ethylene production, while enhancing flavonoid content. Transcriptomic and metabolomic analyses indicated that HTC inhibited the synthesis of phenolic compounds and lignin, modulated glutathione metabolism and genes involved in starch and sucrose metabolism, all contributing to browning prevention. These findings suggest that HTC functions by both directly inhibiting enzymatic browning and enhancing antioxidant defenses, providing a strategy to preserve the quality and extend the shelf life of fresh-cut yams.