Elucidating oxidation-based flavour formation mechanism in the aging process of Chinese distilled spirits by electrochemistry and UPLC-Q-Orbitrap-MS/MS.

The oxygen-based oxidation process is leading toward the understanding of the flavour formation mechanism of aged Baijiu. However, the oxygen-based oxidation process in Baijiu aging is difficult to explore because of (1) the composition of Baijiu produced in different batches varies a lot and (2) the spontaneous oxidation needs several years or even decades to occur. Hence, the flavour formation mechanism of Baijiu aging was investigated using electrochemistry and UPLC-Q-Orbitrap-MS/MS, which enabled us to solve the two difficulties above. The oxidation reaction on gold surface could accelerate Baijiu aging by catalyzing the transformation from alcohols to acids. Although natural aging contributed more diverse compound changes to Baijiu, the oxygen-based oxidation process during natural aging was similar to that in the electrochemical oxidation as a whole. This study provides new insights to flavour formation mechanism of aged liquors and provides a new way for liquor-related enterprises to optimise the aging process.