Volatile and non-volatile metabolomics insights into scenting-driven flavor formation in Chloranthus spicatus scented tea

Chloranthus spicatus scented tea (ZLF) is developed by scenting a tea base with C. spicatus flowers through the scenting process, but its flavor characteristics remain unclear. This study investigated the effects of successive scenting cycles on the sensory characteristics, chemical composition, in vitro antioxidant capacity, and volatile and non-volatile metabolomic profiles of ZLF, with the overall aim of clarifying the chemical changes associated with flavor formation. Multiple scenting rounds increased the contents of free amino acids and soluble sugars, reduced tea polyphenol levels, and enhanced in vitro antioxidant capacity. Six candidate aroma-active compounds, including 1-octen-3-ol, cis-3-hexenyl benzoate, piperonal, eucalyptol, guaiacol, and nonan-1-ol, were screened based on relative odor activity value (ROAV) and variable importance in projection (VIP) values. These compounds may contribute to the sweet, green, violet, herbal, and orchid-like aroma characteristics of ZLF. Scenting was associated with changes in flavonoid glycosides, including decreases in several flavonoid O-glycosides and relative increases in flavonoid C-glycosides. Meanwhile, increased glutamic acid levels may contribute to a mellower and smoother palate. This study provides a reference for optimizing the scenting process of ZLF.