Processing-driven metabolic and aroma shifts in Lingmu tea: insights for novel tea development

Lingmu tea is a traditional non-Camellia beverage, yet its chemical basis and processing-induced changes remain unclear. This study investigated the effects of processing on its composition, flavor, and antioxidant properties using metabolomic and sensory analyses. Processing significantly reduced free amino acids and flavan-3-ols such as epigallocatechin, while increasing complex polyphenols including terchebin and trigalloyllevoglucosan. Organic acids such as gallic acid and lactic acid also increased. Volatile analysis based on relative odor activity values showed that linalool (ROAV = 100) was the dominant aroma contributor in fresh leaves, whereas 1-octen-3-one (ROAV = 100) and dimethyl sulfide (ROAV = 61.75) showed higher contributions after processing. Notably, antioxidant activity exhibited a mechanistic shift from rapid radical scavenging to enhanced overall reducing capacity. These findings provide insights into the compositional and functional transformation of Lingmu tea during processing.