Comparative study of intelligent sensory technologies combined multiple metabolomics in evaluating sensory attributes and health profiles across different grades and varieties of green tea-processed mulberry leaf tea

This study compares the sensory attributes and health profiles of green tea-processed mulberry leaf tea, focusing on different grades and leaves exposed to frost. Electronic nose/tongue, gas chromatography–mass spectrometry, and ultra-performance liquid chromatography-tandem mass spectrometry were employed to assess the flavor characteristics and bioactive components of the teas. Significant differences were found in volatile compounds and bioactive substances across different tea grades, likely influenced by the leaf position of the raw materials. Third-grade tea exhibited the highest concentration of flavor compounds, with pronounced umami and sweet tastes, while lower sourness. Additionally, tea derived from frost-exposed leaves contained higher levels of phenolic compounds, particularly lignans, suggesting enhanced health benefits. Our findings indicate that third-grade tea offers an optimal balance of cost, flavor, and bioactive content compared to higher grades, while frost exposure may boost the health benefits of mulberry leaf tea. • Mulberry leaf tea from frost-exposed leaves contains higher lignans than non-frosted. • Frost-exposed may activate a deglycosidic reaction in lignans with glycoside groups. • No superior flavor and active substances in special and first-grade mulberry leaf teas. • The flavors of third-grade tea with high umami and sweet tastes, but low sour taste. • Third-grade mulberry leaf tea is more cost-effective compared to other grades.