Fan Guangsen, Fu Zhilei, Sun Baoguo, Zhang Yuhang, Wang Xinlei, Xia Yanqiu, Huang Mingquan, Li Xiuting
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing 100048, China; School of Food and Chemical Engineering, Beijing Technology and Business University (BTBU), Beijing 100048, China.
School of Food and Chemical Engineering, Beijing Technology and Business University (BTBU), Beijing 100048, China.
J Biosci Bioeng. 2019 Mar;127(3):309-317. doi: 10.1016/j.jbiosc.2018.08.005. Epub 2018 Sep 18.
Daqu, a complex starting material used for Baijiu production, contains microorganisms, enzymes, and volatile compounds. An important part of Daqu production is aging, but the physicochemical and microbial changes during aging remain largely unknown. This study characterized aging according to physicochemical parameters, volatile compounds, and microbial communities. Aging was found to aid in the stabilization of the physicochemical parameters. Solid-phase microextraction-gas chromatography-mass spectrometry was used to detect 72 types of volatile compounds, which were predominantly alcohols, esters, aldehydes, alkenes, and alkanes. During aging, these compounds changed considerably, but their structures eventually stabilized. A high-throughput sequencing approach was used to analyze the changing composition of the microbial communities. In general, aging helped to enrich and stabilize the microbial population for making Baijiu. A total of 35 bacteria were detected as prokaryotic; among these, 15 had a diversity abundance ratio of more than 1%. The dominant bacteria were from the genus Pantoea, but these decreased with aging, while bacteria from Lactobacillus and Weissella increased. After aging for 2 months, Pantoea, Lactobacillus and Weissella accounted for 0.4%, 54.0%, and 18.9%, respectively. A total of 12 eukaryotic yeast and fungi were detected, the most abundant of which were Incertae_Sedis_incertae_sedis, Saccharomycopsis, Trichocomaceae_unclassified, Pichia, Tremellales_unclassified, and Galactomyces. During aging, the levels of Trichocomaceae_unclassified, Saccharomycopsis, and Galactomyces initially decreased but then increased. Pichia stayed unchanged as aging progressed. In conclusion, aging led to rebalanced interactions among Daqu microbes and was important in improving Daqu quality and ensuring its stability.
大曲是白酒生产中使用的一种复杂原料，含有微生物、酶和挥发性化合物。大曲生产的一个重要环节是陈酿，但陈酿过程中的理化和微生物变化在很大程度上仍不清楚。本研究根据理化参数、挥发性化合物和微生物群落对陈酿进行了表征。发现陈酿有助于理化参数的稳定。采用固相微萃取-气相色谱-质谱联用技术检测到72种挥发性化合物，主要为醇类、酯类、醛类、烯烃类和烷烃类。在陈酿过程中，这些化合物发生了很大变化，但它们的结构最终趋于稳定。采用高通量测序方法分析微生物群落组成的变化。总体而言，陈酿有助于丰富和稳定用于酿造白酒的微生物种群。共检测到35种原核细菌；其中，15种的多样性丰度比超过1%。优势细菌来自泛菌属，但随着陈酿时间的延长而减少，而乳酸杆菌属和魏斯氏菌属的细菌则增加。陈酿2个月后，泛菌属、乳酸杆菌属和魏斯氏菌属分别占0.4%、54.0%和18.9%。共检测到12种真核酵母和真菌，其中最丰富的是分类地位不确定的类群、拟内孢霉属、未分类的曲霉科、毕赤酵母属、未分类的银耳目和半乳糖酵母属。在陈酿过程中，未分类的曲霉科、拟内孢霉属和半乳糖酵母属的含量最初下降，但随后上升。随着陈酿的进行，毕赤酵母属保持不变。总之，陈酿导致大曲微生物之间的相互作用重新平衡，对提高大曲质量和确保其稳定性具有重要意义。
