Characterization of interphase volatile compounds in Chinese Luzhou-flavor liquor fermentation cellar analyzed by head space-solid phase micro extraction coupled with gas chromatography mass spectrometry (HS-SPME/GC/MS)

- We analyzed interphase volatile compounds in the fermentation cellar for the first time.
- We revealed the differences of cellar of different pit ages and spatial positions by HS-SPME/GC/MS.
- Interphase volatile compounds had a close relationship with microbial community structure.
- Multivariate method was efficient to differentiate samples in relation with the variance of concentrations of volatiles.

This study aimed to investigate volatile compounds characteristics of Pit mud (PM), Zaopei (ZP), Huangshui (HS) in Chinese Luzhou-flavor liquor fermentation cellar by HS-SPME/GC/MS. Results indicated that pit age and spatial position had a stronger effect on volatiles than physicochemical properties. A total of 59 volatiles had been identified, and phenylethyl alcohol, butyric acid, pentanoic acid, hexanoic acid, heptanoic acid, ethyl lactate, ethyl hexanoate, ethyl hexadecanoate, ethyl linoleate and ethyl elaidate were dominant, accounting for roughly 66.30%. Additionally, the total level of volatiles significantly increased from upper layer (U) to under layer (D), except for 2-year-MPM and 40-year-MZP, and 40-year-DPM (834.14 mg/kg) had the highest content. PCA explanation plane primarily revealed the main differentiation based on their loading plot values. Results of PLS-DA showed 4-methylphenol and gamma-nonanolactone were correlated with 2-year-PM. In addition to ethyl phenylacetate, ethyl hexanoate, furfuryl hexanoate, ethyl nonanoate, perhydrofarnesyl acetone and 2-acetyl furan were associated with 40-year-PM. Isoamyl hexanoate, octyl octanoate, benzaldehyde and 2-nonenal were with 10-year-PM. 3-methyl-1-butanol, ethyl lactate, ethyl hydrocinnamate and 3-furancarboxaldehyde were related to 2-year-ZP, while ethyl decanoate and ethyl linolenate were relevant to 10-year-ZP. No specific compounds for 40-year-ZP and HS samples were found.