Beijing Laboratory of Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, 100083, China.
Sci Rep. 2018 Feb 21;8(1):3396. doi: 10.1038/s41598-018-21814-y.
Light-flavour Baijiu is a type of Chinese liquor with a pure and mild flavour produced by traditional spontaneous solid-state fermentation. The flavour of this liquor has been found to vary in the different periods of annual production. To explore the factors affecting flavour, the microbiota of the surrounding environment, starter and fermentation process in different periods were investigated. Results showed that the ester content and acidity of light-flavour Baijiu were significantly lower when annual production was resumed after a summer break. HCA plot of volatile flavour profile and bacterial PCoA results indicated that the differences occurred at later stages, mainly due to different structures of Lactobacillus. Correlation analysis by O2PLS indicated that Lactobacillus positively correlated with esters. Species-level analysis showed that the lack of L. acetotolerans on the surface of the jar might cause a lag in fermentation and lower ester content. Thereafter, L. acetotolerans was revived during fermentation and enriched on the surface of the jar, which promoted ester formation. As important sources of L. acetotolerans, the air and fermentation jars played a critical role during fermentation. Therefore, this systematic study on environmental microbial ecology is valuable for quality control and to explore environmental microbiota functions during spontaneous fermentation.
清香型白酒是中国传统固态自然发酵白酒的一种，具有清香纯正、绵甜味长的特点。该酒在不同年度生产周期的风味存在差异。为了探索影响风味的因素，对不同时期的周边环境微生物群、酒曲和发酵过程中的微生物进行了研究。结果表明，夏季停产恢复生产后，清香型白酒的酯含量和酸度明显降低。挥发性风味图谱的 HCA 图和细菌 PCoA 结果表明，差异发生在后期，主要是由于乳杆菌结构不同。O2PLS 的相关性分析表明，乳杆菌与酯类呈正相关。种水平分析表明，曲表面缺乏耐乙酸乳酸杆菌可能导致发酵滞后，酯含量降低。随后，耐乙酸乳酸杆菌在发酵过程中复活并在曲表面富集，促进了酯类的形成。耐乙酸乳酸杆菌作为重要的来源，空气和发酵容器在发酵过程中起着关键作用。因此，对环境微生物生态学的系统研究，对于质量控制和探索自然发酵过程中的环境微生物功能具有重要意义。
