Molecular-level insights into the brewing-dependent chemical diversity, properties, and formation mechanism of Moutai Base baijiu using Fourier transform ion cyclotron resonance mass spectrometry.

The brewing-dependent molecular diversity, properties, and formation mechanism of Moutai (a typical sauce-flavor Baijiu) base Baijiu, were explored using FT-ICR MS combined with various visualization methods. Seven-round Moutai base Baijiu exhibited significant diversity and heterogeneity, containing more unsaturated/saturated reduced molecules. The increased brewing round increased the molecular unsaturation/aromaticity and enhanced the transformation between saturated/oxidized and unsaturated/reduced molecules. Moreover, lignin-/aliphatic-/peptide-/lipid-like molecules dominated the molecular characteristics of Moutai base Baijiu. The basic and acidic components contained more reduced carbohydrate-/lipid-like molecules and oxidized tannin-like/condensed aromatic molecules, respectively, contributing to the molecular stability and diversity, respectively. More unique lipid-like and lignin-like molecules newly formed in the early and late brewing rounds, respectively, and the increased brewing shifted the chemical reaction from a single dominant to a multi-dimensional balance. More unique N-containing molecules (>450 Da) significantly contributed the specific brewing characteristics. These new findings help to understand the molecular-level formation mechanism of Moutai base Baijiu.