Multi-omics profiling reveals the dynamic interplay between processing-induced phytochemical transformation and antioxidant bioactivity in ‘Huangkui’ tea (Camellia sinensis)

‘Huangkui’ (HK), a natural yellow-leaf tea mutant, is usually used as raw materials for producting green tea with unique sensory traits, including bright yellow-green infusions and mellow-refreshing taste. Integrated GC–MS and UPLC-Q-TOF-MS analysis tracked dynamic volatile and non-volatile metabolite changes during processing. In total, 101 volatiles were detected and in which 19 marker compounds were identified. Six aroma compounds were designated as critical aroma contributors (rOAV >1.0). Non-targeted metabolomics revealed 62 non-volatile marker compounds, highlighting catechin conversion into phenolic acids and polymers. During the processing of tea, with the changing of main bioactive compounds, the samples during different processing stage showed different in vitro antioxidant capacity. This multi-omics approach deciphered the biochemical basis of HK's color evolution and flavor development, linking thermal-driven enzymatic inactivation to metabolite preservation. Findings advance precision processing strategies for optimizing functional components in specialty teas.