Enhancing fruity aroma with exogenous tannins in red wines: A study on Marselan and Cabernet Sauvignon

Exogenous tannin addition is widely practiced in Chinese dry red wine production for color stabilization, yet its systematic impact on fermentation-derived aroma compounds remains poorly understood. This study systematically investigated how grape tannins and oak tannins, added at distinct fermentation stages, differentially modulate aroma profile of Vitis vinifera 'Marselan' and 'Cabernet Sauvignon' wines. The results demonstrated that tannin additions markedly influenced esters (e.g., ethyl octanoate, ethyl decanoate), higher alcohols (e.g., 1-hexanol), and key varietal compounds such as linalool and (E)-β-damascenone, with effects peaking during alcoholic fermentation and early bottle aging (3-6 months). Critically, cultivar-specific responses emerged: 'Marselan' showed greater sensitivity in ester concentrations, while 'Cabernet Sauvignon' exhibited more pronounced changes in higher alcohols. This work advances mechanistic understanding by revealing that tannins enhance aroma compound formation, release, and retention, intensifying red berry, fresh fruit, and herbaceous notes. These findings provide evidence-based strategies for targeted tannin management to optimize wine aroma in industrial-scale production.