Phenolic matrix effect on aroma formation of terpenes during simulated wine fermentation - part II: Flavanols and flavonols.

To investigate the phenolic matrix effect of flavanols and flavonols on terpene aroma formation during wine fermentation, simulated grape juice was fermented with or without the addition of extra terpene glycosides, catechin, or quercetin. Monitoring changes in free terpene content during fermentation by gas chromatography-mass spectrometry and sensory evaluation of the wines confirmed that catechin and quercetin inhibited both the formation and volatilization of free terpenes and affected the fruity aroma. Quantum mechanical calculations showed that the spontaneous binding of catechin/quercetin to linalool or its glycoside is primarily driven by hydrogen bonding and dispersive forces, with catechin and quercetin exhibiting stronger binding affinities to the glycoside (-23.94 kJ/mol) and linalool (-20.80 kJ/mol), respectively. This theoretical finding suggests a molecular mechanism in which phenolic species influence the molecular morphology of terpene glycosides and free terpenes, thereby affecting terpene glycoside hydrolysis, free terpene volatilization, and the wine overall olfactory characteristics.