Chemical Basis and Taste Mechanism of Strong-Aroma Baijiu Revealed by Integrated Metabolomics and Sensory Analysis

This study systematically elucidated the taste quality of baijiu using a multi-omics approach. An electronic tongue objectively evaluated the basic taste attributes of commercial strong-aroma baijiu, revealing that the significant divergence between sourness and umami intensities serves as a key indicator for distinguishing baijiu products (p < 0.05). Partitioning Around Medoids (PAM) clustering analysis classified 44 strong-aroma baijiu samples into three distinct clusters, one of which displayed a characteristic “high-umami, low-sourness, and moderately salty” profile corresponding to the sensory attributes of premium baijiu. Liquid chromatography–tandem mass spectrometry (LC–MS/MS)-based screening further identified key non-volatile metabolites, demonstrating that several small peptides (e.g., His-Asn-Ile, Pro-Ala-Phe) and certain low-molecular-weight compounds exhibited significant positive correlations with umami intensity (p < 0.05), while some also correlated negatively with sourness or positively with saltiness (p < 0.05). Furthermore, samples with higher saltiness intensity contained significantly elevated concentrations of sodium (Na+), calcium (Ca2+), and magnesium (Mg2+) ions (p < 0.05). Integrated analysis revealed that small peptides directly or indirectly influence baijiu taste perception by interacting with taste receptors and engaging in odor–taste synergy, whereas specific metabolites reduce sourness or enhance the persistence of saltiness. This study elucidates the molecular basis of the “high-umami, low-sourness, and moderately salty” profile of baijiu, providing essential insights for flavor evaluation and optimization of premium baijiu products.