Metabolomic and transcriptomic profiles reveal the mechanism of browning inhibition of Pueraria lobata by heat treatment

This study investigated the mechanism of browning inhibition by heat treatment (70 °C for 5 min) by analyzing its effects on polyphenol oxidase (PPO) activity, browning index, antioxidant activity, metabolite and gene expression profiles using physiological, metabolomic and transcriptomic approaches. Heat treatment inhibited PPO activity and delayed the browning of Pueraria lobata , while increasing free radical scavenging activity and total flavonoid content. Metabolomic analyses revealed that catechins, caffeic acid, tyrosine and coumaric acid might be the major metabolites associated with the browning of Pueraria lobata , whereas flavonoid and isoflavonoid metabolites might be beneficial for delaying browning. Multi-omics analysis revealed that the tyrosine metabolism and isoflavone biosynthesis pathways were enriched and played crucial regulatory roles in browning. This study provides a practical strategy for improving quality in post-harvest processing and deep processing of Pueraria lobata . Future research need focus on the spatial variation analysis of these browning-related metabolites in Pueraria lobata .