Analysis of quality variations in Acer truncatum leaf tea made with different particle sizes of ground leaves, employing electronic nose and tongue technology

The leaves of Acer truncatum are rich in bioactive compounds such as flavonoids and chlorogenic acid, making them a promising resource for functional tea development. However, the impact of processing parameters on tea quality remains poorly understood. This study investigated the effect of particle size on the quality of A. truncatum leaf tea. A total of 144 compounds with relative contents above 100 μg/g were identified, among which flavonoids were the most abundant. The leaves were ground into four particle sizes (5-, 10-, 20- and 30-mesh) for subsequent analysis. Tea infusions were analyzed for several components, aroma, and taste using E-nose and E-tongue. Among 301 volatile compounds, 12 were key odorants (OAV ≥ 1.0), with propanoic acid octyl ester, β-damascenone, cyclohexanone and citral being major contributors. Artificial sensory evaluation awarded the 20-mesh sample the highest score; E-nose/E-tongue analyses confirmed its balanced flavors profile with fruity/floral aroma and umami-sweet taste. The 5-mesh sample gave higher yields of bioactive compounds (total flavonoids, chlorogenic acid, free amino acids, soluble sugars) across two brews. This study provides a scientific basis for optimizing A. truncatum tea processing. • Integrated E-nose, E-tongue, and metabolomics for A. truncatum tea evaluation. • June leaves (highest flavonoids and chlorogenic acid) were optimal raw material. • 20-mesh optimized sensory quality; 5-mesh maximized bioactive yield. • Four key odorants defined tea aroma. • Particle size critically influenced infusion color and bioactive compound release.