基于传统虾酱特征风味指纹图谱构建的优势微生物发酵调控机制

Fermented foods exhibit distinct flavors primarily because of diverse microbial flora, metabolic pathway complexity, and various responses to changes in microflora during fermentation. In this study, an aroma model based on molecular sensory science is established through GC–MS, GC–O, aroma extraction, and stable isotope dilution analysis(AEDA, SIDA). Different types of aroma are recombined and eliminated. Taste active flavor substances are then analyzed through LC–MS et al. E-nose, E-tongue, and sensory evaluation are also integrated. Key flavor compounds in shrimp pastes are decomposed at a molecular level. The characteristic flavors of shrimp pastes are also evaluated quantitatively and qualitatively in terms of their chemical molecules. The characteristic flavors fingerprint of traditional shrimp paste will be established. Microorganisms are screened and identified in different fermentation stages of traditional shrimp pastes to monitor flavor formation as changes occur during microbial fermentation. These procedures are also performed to verify the dominant bacteria responsible for the main flavor. A single-phase fermentation model of complex bacteria is further developed. The flavor-oriented fermentation parameters of dominant microorganisms and the changes in endogenous and exogenous enzymes, microorganisms, and active flavor substances are also explored in terms of traditional shrimp paste fermentation. The changes in the microflora of the dominant microorganisms and the response system of the characteristic flavors are examined. This study provides theoretical and experimental bases for the microbial regulation of shrimp paste fermentation.

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，发酵过程中菌相变化规律与风味特征具有重要的响应关系。本项目基于分子感官科学理论，采用GC-MS、GC-O及香气提取物和稳定同位素稀释分析（AEDA、SIDA），建立香气模型，并进行香气重组及消除实验；再以LC-MS等分析滋味活性物质；集成E-nose、E-tongue和感官鉴评，剖析虾酱中关键风味化合物，从分子层面定性、定量揭示虾酱特征风味的化学本质，构建传统虾酱特征风味指纹图谱。然后对传统虾酱不同发酵阶段的微生物进行筛选和鉴定，追踪发酵过程中微生物变化对风味形成的影响，确定主要风味优势菌。设计单一及复合菌相的发酵模型，对照传统虾酱发酵过程，探究风味导向的优势微生物发酵参数，研究体系中内外源酶、微生物及风味活性物质等的变化，解析优势微生物菌相变化与特征风味的响应机制，为探索并实现虾酱的微生物发酵调控提供理论依据和实验数据。

中国传统发酵虾酱风味独特，营养丰富，能否解析其发酵过程中微生物的种群变化规律及对风味形成的影响，是传统虾酱产业化发展面临的重要瓶颈，也是食品科学工作者亟待解决的重要问题。.利用高通量测序技术对传统虾酱中细菌组成进行分析，并采用传统培养方法，对传统虾酱不同发酵阶段样品中的菌种进行培养分离鉴定。采用SPME-GC-MS对各个发酵阶段的虾酱样品中的挥发性成分进行检测，共检测出77种物质，包括醇类、酮类、醛类、含氮化合物、含硫化合物、烃类、酸类、酯类以及其它化合物。采用O2PLS模型对挥发性成分与细菌组成之间的相关分析，结果表明虾酱发酵过程中挥发性成分的变化与细菌菌群有较强的相关性。其中Lactobacillus、Tetragenococcus和Salimicrobium等属对挥发性成分贡献最大，且与成熟虾酱中多种特征香气成分有很高的正相关性 (ρ>0.9) ，与产生不愉快气味的物质呈较高负相关性 (ρ<-0.7) ，说明这3个菌属在虾酱发酵的各个阶段对挥发性成分的变化起着重要的作用，是影响虾酱品质的重要菌属。.基于感官品评和电子鼻技术进行主成分和聚类分析，采用SPME-GC-MS、GC-O及香气提取物稀释分析，建立香气模型，并进行香气重组及消除实验；以“色谱指纹图谱相似度评价系统”进行数据比对，得到包含醛类、酮类和醚类等在内的210种挥发性物质，建立了包含反-2-辛烯醛、2-乙基己醇、苯乙醛、苯乙酮、壬醛、等典型挥发性成分的香气指纹图谱. 通过溶剂辅助蒸发萃取后，用GC-MS检测传统虾酱，通过GC-O分析共鉴定得到42种香气活性物质。香气指纹图谱的初步构建，为鉴别不同地域特殊风味的虾酱产品提供参考。.中国传统发酵虾酱是具有良好产业化前景的海鲜调味品，从机理上探知微生物对风味品质的作用和影响，获取风味优势微生物及其发酵参数，为探索并实现虾酱的微生物发酵调控提供了理论依据和实验数据。