Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, PR China.
National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, PR China.
Int J Food Microbiol. 2021 Mar 2;341:109070. doi: 10.1016/j.ijfoodmicro.2021.109070. Epub 2021 Jan 20.
Zhejiang Rosy Vinegar (ZRV) is a traditional condiment in Southeast China, produced using semi-solid-state fermentation techniques under an open environment, yet little is known about the functional microbiota involved in the flavor formation of ZRV. In this study, 43 kinds of volatile flavor substances were identified by HS-SPME/GC-MS, mainly including ethyl acetate (relative content at the end of fermentation: 1104.1 mg/L), phenylethyl alcohol (417.6 mg/L) and acetoin (605.2 mg/L). The most abundant organic acid was acetic acid (59.6 g/L), which kept rising during the fermentation, followed by lactic acid (7.0 g/L), which showed a continuously downward trend. Amplicon sequencing analysis revealed that the richness and diversity of bacterial community were the highest at the beginning and then maintained decreasing during the fermentation. The predominant bacteria were scattered in Acetobacter (average relative abundance: 63.7%) and Lactobacillus (19.8%). Both sequencing and culture-dependent analysis showed Lactobacillus dominated the early stage (day 10 to 30), and Acetobacter kept highly abundant from day 40 to the end. Spearman correlation analysis displayed that the potential major groups involved in the formation of flavor compounds were Acetobacter and Lactobacillus, which were also showed strong relationships with other bacteria through co-occurrence network analysis (edges attached to Acetobacter: 61.7%; Lactobacillus: 14.0%). Moreover, structural equation model showed that the contents of ethanol, titratable acid and reducing sugar were the major environmental factors playing essential roles in influencing the succession of bacterial community and their metabolism during the fermentation. Overall, these findings illuminated the dynamic profiles of bacterial community and flavor compounds and the potential functional microbes, which were expected to help us understand the formation of flavor substances in ZRV.
浙江红曲醋（ZRV）是中国东南地区的一种传统调味品，采用半固态发酵技术在开放式环境下生产，但对于参与 ZRV 风味形成的功能微生物群知之甚少。在这项研究中，通过 HS-SPME/GC-MS 鉴定出 43 种挥发性风味物质，主要包括乙酸乙酯（发酵结束时的相对含量：1104.1mg/L）、苯乙醇（417.6mg/L）和乙酰基丙酮（605.2mg/L）。最丰富的有机酸是乙酸（59.6g/L），在发酵过程中不断上升，其次是乳酸（7.0g/L），呈持续下降趋势。扩增子测序分析显示，细菌群落的丰富度和多样性在发酵开始时最高，然后在发酵过程中保持下降趋势。优势细菌分散在醋杆菌（平均相对丰度：63.7%）和乳杆菌（19.8%）中。测序和培养依赖分析均显示，乳杆菌在早期（第 10 天至 30 天）占主导地位，而醋杆菌从第 40 天到发酵结束一直保持高度丰富。Spearman 相关分析显示，参与风味化合物形成的潜在主要菌群为醋杆菌和乳杆菌，通过共现网络分析（连接到醋杆菌的边缘：61.7%；乳杆菌：14.0%）与其他细菌也显示出很强的关系。此外，结构方程模型显示，乙醇、总酸和还原糖含量是影响发酵过程中细菌群落演替及其代谢的主要环境因素。总的来说，这些发现阐明了细菌群落和风味化合物的动态特征以及潜在的功能微生物，这有望帮助我们理解 ZRV 中风味物质的形成。
