Analysis of Burnt Flavor Substances in Nongxiangxing Base Baijiu

In order to investigate the burnt flavor substances of Nongxiangxing base baijiu, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the flavor components of base baijiu with normal and burnt flavor. The results showed that a total of 139 flavor substances were detected, of which 20 could be used to differentiate between the two types of base baijiu. Cluster heatmap analysis showed that nine flavor substances, 2,4-di-tert-butylphenol, ethyl laurate, butyl caproate, hexyl caprylate, heptyl heptanoate, pentyl caproate, hexyl caproate, caproic acid, and caprylic acid, were more predominant in burnt-flavor base baijiu. Sensory reconstitution, omission, and addition experiments revealed that the burnt flavor was not ascribed to a single compound but rather to the interaction of multiple compounds. 2,4-Di-tert-butylphenol and esters were found to be significantly associated with the burnt flavor of Nongxiangxing base baijiu.