发酵苹果醋特征风味物质的鉴定及其机理研究

The process of apple cider vinegar fermentation is a complex microbial transformation process. The flavor substances mainly include the substance of taste and smell, and the flavor quality of apple cider vinegar is formed by their collaborative effects. Now, apple vinegar flavor substances and their mechanisms are still in the stage of exploration. In this project, HPLC, HS SPME/GC - MS and other modern classical instrument analysis method are applied for determing the fermented apple cider vinegar compounds of taste and volatile, and flavor characteristics and flavor intensity are determined by taste activity value and sniffing device (GC/O). Meanwhile, the characteristic substances of apple cider vinegar flavor are identfied by the methods of principal component analysis and clustering analysis. For senior ester iso-amyl acetate, in order to clear transformation and metabolic pathway of its senior ester, exogenous standard addition method are applied for studying the effect of precursor contents (including amyl acetate concentration of ethanol, sugar, leucine) on the characteristic substances of apple cider vinegar flavor. To clear the correlation between their activities and characteristic substances of flavor and reveal the forming mechanism of characteristic substances, the activity of ester oxidase and alcohol dehydrogenase participated in the esters metabolism are determined in the fermentation process. All of these will provide a theoretical basis for controlling the quality of the apple cider vinegar product and detetming the adulteration.

苹果醋发酵过程是一个复杂的微生物转化过程，主要风味物质为味感和嗅感物质，它们共同协同相互作用形成苹果醋特有的风味质量，目前苹果醋特征风味物质及其机理研究尚处于探索阶段。本项目拟采用HPLC、HS-SPME-GC-MS等现代经典仪器分析方法，系统研究发酵苹果醋味感成分和挥发性嗅感成分，通过滋味活度值、嗅闻装置(GC/O)确定风味特征及风味强度，采用主成分分析、聚类分析等方法鉴定出特征风味物质；以高级酯乙酸异戊酯为例，采用外源加标法研究前体物乙酸、异戊醇、蔗糖、氨基酸（亮氨酸）浓度对特征风味物质含量的影响，探索以乙酸异戊酯为例的高级酯的转化、代谢途径；通过对影响特征风味物质合成的相关酶酯氧化酶、醇脱氢酶活性的测定，明确它们之间的相关性，揭示特征风味物质形成机理；为苹果醋产品质量控制及掺伪掺假检测提供理论依据。

苹果醋发酵过程是一个复杂的微生物转化过程，主要风味物质相互协同共同作用形成苹果醋特有的风味质量，苹果醋品质的优劣对苹果醋产业的发展有着重要的影响，发酵苹果醋特征风味物质的研究确定，在苹果醋质量评价体系及掺伪掺假检测中占有重要位置，目前苹果醋特征风味物质及其机理研究尚处于探索阶段。本项目按照基金委项目计划任务书要求，以发酵苹果醋为研究对象，综合应用微生物学、HPLC、HS-SPME-GC-MS、电子鼻、电子舌等研究方法和技术手段，首次对我国不同产区苹果原料、不同菌种发酵苹果醋产品进行了系统研究，确定了发酵苹果醋中主要特征物质，建立了苹果醋样品有机酸、氨基酸液相色谱指纹图谱并对发酵苹果醋样品进行较好的归类区分；借助电子舌、电子鼻分析评价，建立了苹果醋样品中气味、滋味模型并进行分析验证，实现了不同苹果醋样品快速准确的区分判别，为苹果醋品质感官评价提供量化指标。在上述工作基础上，初步研究了苹果醋中主要发酵菌株的生长代谢机制及主要风味物质乙酸苯乙酯、乙酸异戊酯的形成机理，建立了苹果醋发酵特征物质调控关键工艺控制点。通过本项目的实施构建了一套苹果醋特征风味物质的评价方法，以及特征物质的形成及调控机制，这些工作将为苹果醋发酵深入系统研究提供重要的理论依据。项目执行期间发表论文7篇，撰写发明专利3项，起草备案企业标准2项，开发新产品2种，购置实验仪器设备5件（台），改造微生物实验室1间。