Decoding off-odour profiles of six typical defective sauce-flavour Baijiu by integrating multidimensional detection and molecular docking
Hong Zhang, Ying Huang, Furong Wang, Junjun He, Chunlin Zhang, Feng He, Jing Wang, Zhenlan Zhang, Jun Qu, Xudong Liu, Yu Mu
Abstract
Flavour imbalance significantly impairs sauce-flavour Baijiu quality; however, the key off-odour compounds remain unclear. Multidimensional detection and molecular docking were employed to explore the flavour profiles of six typical defective off-odour sauce-flavour Baijiu samples (mud-like, green, rancid-like, pickle-like, oil-like and burnt). Quantitative sensory analysis showed defective samples featured unique off-odours and varied from normal ones in sauce-flavour Baijiu aroma. E-nose analysis revealed that mud-like off-odour most significantly differed from normal Baijiu, followed by oil-like and green off-odours, whereas rancid-like, pickle-like and burnt off-odours exhibited minor differences. Meanwhile, 73 and 134 volatiles were detected via gas chromatography-mass spectrometry and gas chromatography-ion mobility spectrometry, respectively, with 14 recurring compounds. Chemometrics identified 61 differential compounds between off-odour and normal samples, and 34 potentially off-odour contributors were screened by odour activity value and relative odour activity value. Molecular docking emphasised key compounds associated with each off-odour, such as 1-octene for mud-like, ethyl octanoate for green, naphthalene for rancid-like, p-dichlorobenzene for pickle-like, butyl 2-methylbutyrate for oil-like and ethyl 3-methylbutanoate for burnt off-odours. These compounds primarily form stable conformations with receptors through hydrophobic interactions, causing odor perception. This study provides systematic insights into the typical off-odour of sauce-flavour Baijiu, forming a basis for its quality refinement. • Combined E-nose, GC–MS, and GC–IMS characterized off-odour sauce-flavour Baijiu. • The off-odour of sauce-flavour Baijiu were induced by flavour compound imbalance. • Sixteen key differential compounds identified in six defective sauce-flavour Baijiu. • Hydrophobic binding of off-odourants to olfactory receptors drives odour perception.