Molecular insights into the protective effects of phenolic acid addition on blueberry wine sensory profiles via sensomics and quantum mechanics.

Blueberry wine suffers from concurrent losses of color and aroma volatiles during bottle aging. This study demonstrates that the timing of phenolic acid supplementation can selectively steer functional outcomes toward either color stabilization or aroma preservation. Gallic acid (GA) and caffeic acid (CA) were added at 200 mg/L either before or after alcoholic fermentation, and the wines were bottle-aged for six months. Pre-fermentative GA addition provided the strongest chromatic protection, maintaining redness (a∗) and chroma (Cab∗) approximately 9% and 8% higher, respectively, than the control. In contrast, post-fermentative addition of either GA or CA significantly enhanced the retention of linalool and ethyl hexanoate, which were quantified by HS-SPME-GC × GC-qTOFMS, with increases of about 46% and 49%, respectively, leading to intensified floral and fruity sensory attributes, as confirmed by sensory addition tests. Quantum mechanical calculations suggest that post-fermentative GA forms non-covalent complexes with these aroma compounds through hydrogen bonding and dispersion forces, thereby suppressing their release. Conversely, pre-fermentative GA was associated with reduced accumulation of both linalool and ethyl hexanoate, potentially due to modulation of glycosidic precursor hydrolysis or promotion of anthocyanin-pyruvic acid condensation. These findings establish a practical "timing splits function" principle, enabling targeted optimization of blueberry wine quality through strategic phenolic acid addition.