Variation of aroma compounds in soy sauce aroma type baijiu during aging: Focusing on the regulatory effect of ethyl lactate on aroma release

Aging is crucial for enhancing the flavor quality of Baijiu. This study investigated soy sauce aroma type Baijiu, analyzing 76 base liquor samples from 15 years (2010–2024) using gas chromatography–mass spectrometry (GC–MS) to quantify 77 volatile compounds. Results revealed that during aging, esters generally showed a decreasing trend, while acids, alcohols increased. Combined with results of multivariate analysis, ethyl lactate was selected for further study due to its greatest absolute change in concentration. Using headspace solid-phase microextraction combined with GC–MS, it was demonstrated that ethyl lactate inhibits the release of 28 aroma-active compounds, with this effect varying by chemical class and being less pronounced for short-chain acids. Quantum chemical calculations revealed that this selectivity for acids is mainly attributed to their strong self-association into stable dimers, which creates a competitive inhibition against binding with ethyl lactate. Furthermore, sensory evaluation confirmed the effects ethyl lactate on overall flavor of the liquor.