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• Raw material grade and processing critically shape tea flavor profiles. • Curling enhances aroma and umami, reduces astringency and bitterness. • 38 aroma-active volatiles define QC1′s floral, green, and fruity character. • Provided practical guidance for QC1 tea optimization. Tea quality is synergistically shaped by raw material grade and processing, yet existing research has primarily focused on the processing stage, with systematic evaluations of the role of raw materials remaining insufficient. This study systematically investigated the flavor chemistry of the 'Qiancha 1′ (QC1) tea plant cultivar across tea types from multi-grade raw materials. Fresh leaves of QC1 (one-bud-one-leaf, one-bud-two-leaves, one-bud-three/four-leaves, open surface leaves) were processed into eight distinct tea products (green, black, oolong). Key taste components (catechins, theanine, caffeine, 20 amino acids, 18 flavonoids) were quantified via HPLC and LC-MS. Aroma volatiles (366 compounds) were analyzed using headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (HS-SPME/GC × GC-TOF-MS). Multivariate analysis revealed significant compositional shifts driven by raw material grade and processing. Tea from one-bud-two-leaves exhibited the highest theanine content. The curling process markedly increased amino acids and aroma volatiles while reducing catechins and flavonoids levels. Lipids and esters dominated the volatile profile. Thirty-eight key aroma-active compounds were identified, defining QC1′s characteristic floral, green, and fruity notes. This work provides a chemical basis for optimizing QC1 tea processing, recommending one-bud-one/two-leaf raw materials for curly green or black tea to enhance characteristic flavor quality.
Qiao et al. (Fri,) studied this question.