Dynamic changes in metabolites during the manufacture of three distinct flavor types of Tieguanyin

The formation mechanisms for different aroma types of Tieguanyin was investigated. In this study, the same fresh leaves were processed into three Tieguanyin samples with distinct aroma types (fresh floral scent, flower and fruit scent, sweet fruity scent). Based on sensory evaluation and metabolomic analysis, the dynamic changes of aroma- and taste-related compounds in three Tieguanyin tea samples during processing process were investigated. Sensory evaluation results demonstrated that subtle variations in processing parameters resulted in distinct flavor types of Tieguanyin. Metabolomic analysis identified 199 taste-related metabolites and 82 aroma-related compounds. The fresh floral-scented Tieguanyin had more catechins and L-theanine. Linalool, 1-octanol, and benzeneacetaldehyde were identified as the key contributors to the overall aroma of Tieguanyin. Short time (340 min) of shaking and heavy fixation (260 °C, 5.5 min) produced fresh floral scented Tieguanyin tea. These findings provide a theoretical basis for the comprehensive understanding of flavor formation of Tieguanyin tea.