Impact of processing methods in shaping taste, flavor, antioxidants, and metabolites in teas (Camellia sinensis): A multi-method analysis

This study systematically examined the effects of processing techniques on the flavor profiles and functional attributes of tea derived from fresh leaves ( Camellia sinensis ) of identical origin. Pu-erh raw tea (PRT), white tea (WT), and black tea (BT) were produced through distinct processing protocols (non-fermented, lightly fermented, and fully fermented, respectively). Antioxidant activity and sensory characteristics were evaluated alongside comprehensive metabolomic analyses using GC-IMS, GC–MS, and UHPLC-QTOF-MS. PRT exhibited superior antioxidant capacity with pronounced bitterness and astringency, whereas WT displayed fruity-sweet notes and BT demonstrated a mellow profile linked to fermentation. Metabolomic profiling identified six discriminative biomarkers and two pivotal compounds differentiating tea types, alongside six key metabolic pathways (e.g., secondary metabolite biosynthesis) driving compositional variations. These findings elucidate processing-induced biochemical transformations, offering insights for quality optimization and consumer-oriented tea selection.