嗜盐菌代谢影响传统发酵虾酱特征风味形成的分子机制

发酵食品独特风味的形成主要来自微生物菌群的多样性和代谢途径的复杂性，基于传统虾酱风味指纹图谱的优势微生物发酵机制研究发现，嗜盐菌代谢对特征风味形成影响显著。本项目分离鉴定传统虾酱发酵过程中产蛋白酶、支链氨基酸转氨酶、核酸酶等的嗜盐菌。设计单一及复合菌发酵模型，采用LC-Q/TOF-MS及NMR等代谢组学方法，以味活度值（TAV）、等效鲜味浓度（EUC）等指标鉴定味觉关键活性成分。利用GC-IMS、GC-O-MS及香气提取物（AEDA）和稳定同位素稀释分析（SIDA）等剖析关键香气化合物。集合多种组学和分子感官科学分析技术，构建风味代谢网络，研究嗜盐菌Ehrlich通路、支链氨基酸降解途径及支链醛形成的复杂化合物体系。解析传统发酵虾酱特征风味形成的群体微生物代谢及协同作用，阐明盐胁迫启动的嗜盐菌特异性代谢物生物转化的分子机制，为探索传统虾酱风味导向的微生物发酵调控提供理论依据和实验数据。

Fermented foods exhibit distinct flavors primarily because of diverse microbial flora, metabolic pathway complexity, and various responses to changes in microflora during fermentation. Our preliminary studies about dominant microbial fermentation mechanism on traditional shrimp paste flavor have indicated that the metabolism of halophilic bacteria has significant effects on characteristic flavor formation. In this study, fermentation models for the single and complex bacterial phases are developed to extract enzymes, such as protease, branched-chain amino acid aminotransferase and nuclease, that are decomposed by halophilic bacteria, through morphology, physiology, biochemistry, and molecular biology identification techniques. Specifically, the complex metabolites in the halophilic fermentation model are tracked by metabolomics methods such as LC-Q/TOF-MS and NMR. Key active components of taste are measured by taste activity value (TAV), and equivalent umami-flavor concentration (EUC), etc. An aroma model is established by GC-IMS, GC-O-MS, aroma extraction and stable isotope dilution analysis (AEDA, SIDA). The complex compound system formed by the halophilic bacteria Ehrlich pathway, branched-chain amino acid synthesis pathways, and branched-chain aldehydes is analyzed by multi-omics technology. The study explores the microbial succession during forming the distinctive flavor of traditional fermented shrimp paste and elucidates the molecular mechanism of biotransformation for the specific metabolites of halophilic bacteria under salt stress. Significantly, this project provides theoretical and experimental bases for the flavor-oriented microbial shrimp paste fermentation regulation.