Analysis of Unique Flavor Metabolites and Seasonal Variations of the Special Tea Plant Cultivar of Fuliang Tea, a Geographical Indication Product

This study investigated the key flavor metabolites and their seasonal variation mechanisms in the Fuliang green tea-specific cultivar ‘Fuliang Zhuye 1’ (FLZY). Results showed that cultivar identity shaped the metabolite profile more strongly than spring seasonal changes. Compared with ‘Fuding Dabaicha’ (FDDB), FLZY better represented the traditional flavor profile of Fuliang green tea, which is characterized by floral aroma and a sweet aftertaste. Using multimodal flavoromics, we identified a set of key aroma- and taste-active compounds capable of reconstituting FLZY’s characteristic flavor. Omission experiments suggested that several amino acids—including L-theanine, L-glutamic acid, L-aspartic acid, and L-glutamine—enhanced umami, sweetness, mellowness, and sweet aftertaste. These amino acids also reduced bitterness and astringency. Notably, their individual dose-over-threshold values were all below one. The springtime decline of these components correlated with a reduction in overall flavor intensity. Furthermore, FLZY accumulated markedly higher levels of kaempferol-3-O-rutinoside than FDDB. This difference may have contributed to its enhanced sweet aftertaste. These findings provide references for protecting the traditional flavor of geographical indication tea products and for targeted tea plant breeding.