Effects of composite steaming and drying process on the taste and aroma of pomelo black tea via metabolomics and sensory histology techniques

This study integrated metabolomics, electronic tongue, and molecular docking to investigate how a multi-stage steam-drying process influences the flavor characteristics of pomelo black tea. Results showed that continuous steam-drying can significantly reduce bitterness and umami, and it could also promote the hydrolysis of flavonoid glycosides such as naringenin and the accumulation of organic acids such as linolenic acid, thereby increasing acidity while reducing bitterness. Volatile component analysis indicated that heat-sensitive terpenes such as <i>γ</i>-terpinene was significantly reduced due to oxidative degradation. Aldehydes and esters, including undecanal and neryl acetate, might compensate for this loss of aroma through thermal conversion. This research also found that hydrogen bonds and hydrophobic interactions were key to the binding of aroma compounds to olfactory receptors. Overall, this study provides molecular- and sensory-level evidence linking moist heat processing to coordinated changes in taste- and aroma-related compounds in pomelo black tea.