郫县豆瓣“翻、晒、露”期间微生物群落及挥发性风味物质的变化

Changes in Microbial Community and Volatile Flavor Substances during the “Turning, Drying and Dewing” Process of Pixian Broad-bean Paste

摘要:

该研究采用气相色谱质谱串联仪（GC-MS）、高通量测序（HTS）技术分析郫县豆瓣工业发酵“翻、晒、露”期间挥发性风味物质（VFS）的变化与微生物群落的演替，并分析关键VFS与优势菌群的相关性。结果表明，“翻、晒、露”期间的VFS呈动态变化，尤其是体现特色风味的酯类、醇类物质在这一过程富集，VFS 总含量呈先增加后降低的趋势。Bacillus、Staphylococcus、Levilactobacillus、Tetragenococcus、Oceanobacillus、Enterobacter、Weissella、Aspergillus及多种酵母类菌属为“翻、晒、露”期间的优势微生物。Pearson相关性分析表明，上述优势菌群与35种关键香气成分（OAV>1）具有相关性。其中，Bacillus与3-甲硫基丙醛极显著正相关（P<0.001）；愈创木酚与Zygosaccharomyces极显著正相关（P<0.001）、与Wickerhamiella 显著正相关（P <0.01）；Starmerella与十四酸乙酯显著正相关（P<0.01）；Weissella、Kazachstania、Vishniacozyma、Fusarium及Alternaria与异戊腈均显著正相关（P<0.01）。“翻、晒、露”过程有益于郫县豆瓣VFS的积累和风味的改善，发酵郫县豆瓣的优势菌群与部分关键VFS存在显著的正相关性，可通过调控期间的微生物群落影响产品风味。研究结果有助于阐明郫县豆瓣特色风味形成的机理及对工业“翻、晒、露”工艺的理解。

Abstract:

In this study, the changes of volatile flavor substances (VFS) and succession of microbial community in the “turning, drying and dewing” process during industrially fermentation of pixian broad-bean paste (PXDB) were investigated by gas chromatography-mass spectrometry (GC-MS) and high-throughput sequencing (HTS) , and the correlation between the key VFS and the dominant microbial community was also analyzed. The results showed that the VFS underwent dynamic changes, especially the esters and alcohols imparting characteristic flavor were enriched and the total VFS content increased gradually then decreased, during the “turning, drying and dewing” process. Bacillus, Staphylococcus, Levilactobacillus, Tetragenococcus, Oceanobacillus, Enterobacter, Weissella, Aspergillus and multiple yeast genera were the dominant microorganisms during the “turning, drying and dewing” period. Pearson correlation analysis showed that the above dominant floras previously mentioned were correlated with 35 key aroma components (OAV>1). Among them, Bacillus was significantly and positively correlated with 3-methylthiopropionaldehyde (P<0.001). 2-Methoxyphenol was extremely significantly and positively correlated with Zygosaccharomyces (P<0.001) and significantly and positively correlated with Wickerhamiella (P<0.01). Starmerella was significantly and positively correlated with ethyl myristate (P<0.01). Weissella, Kazachstania, Vishniacozyma, Fusarium and Alternaria were significantly and positively correlated with 3-methylbutanenitrile (P<0.01). The “turning, drying and dewing” process was beneficial to the accumulation of the main VFS and the improvement of PXDB’s flavor. A significant and positive correlation was detected between the dominant floras and some key VFS in the fermented PXDB, indicating that product flavor could be affected by regulating the microbial community during a specific period. The results of this study are helpful to clarify the mechanism underlying the formation of the characteristic flavor of PXDB and the understanding of the “turning, drying and dewing” process of industrially fermented PXDB.