Study on volatile compounds in fermented grains of light-flavor Niulanshan Erguotou Baijiu

In order to study the volatile compounds in the fermented grains of Niulanshan Erguotou Baijiu, the volatile compounds of vessel-loading and vessel-unloading fermented grains from different fermentation vessels (ground jars and ceramic tile tanks) in Niulanshan Erguotou Baijiu were identified by headspace solid phase microextraction (HS-SPME), solvent-assisted flavor evaporation (SAFE) combined with GC-MS and two-dimensional gas chromatography-mass spectrometry (GC×GC-MS), and the principal component analysis (PCA) was carried out for esters, alcohols and acids. The results showed that a total of 317 volatile compounds were identified, mainly esters, alcohols and olefins, which were 83, 33 and 30, respectively. 199, 225, 175 and 200 compounds were determined in vessel-loading fermented grains from ceramic tile tanks, vessel-unloading fermented grains from ceramic tile tanks, vessel-loading fermented grains from ground tanks, and vessel-unloading fermented grains from ground jars, respectively, and the contents were different. The compound content in the vessel-unloading fermented grains [(595.37±42.18) mg/kg] was significantly higher than that in the vessel-loading fermented grains [(332.47±25.02) mg/kg]. Meanwhile, the volatile compounds content in fermented grains fermented by ground jars [(489.83±34.84) mg/kg] was higher than that in fermented grains fermented by ceramic tile tanks [(438.01±32.36) mg/kg]. Principal component analysis could significantly distinguish volatile compounds in different fermentation vessels and brewing stages. The results provided a scientific basis for optimizing the fermentation process and improving the flavor quality of Niulanshan Erguotou Baijiu in the future.