基于脂质代谢组学解析中华绒螯蟹关键香气物质的形成机制

Chinese mitten crab (Eriocheir sinensis) is one of the popular and delicious aquatic foods due to its unique odor. Aldehydes, orignated from lipid thermal degradation and oxidation, are the major odorant sources during the crab steaming. However, up to date, it is largely unclear for the formation mechanism of the key odorants for E.sinensis. The present project was firstly designed to compare the changes of lipid class and fatty acid contents in different edible parts of crabs before and after steaming. The relationship between the key odorants emissions and lipids changes will be found for the different edible parts, and the major edible tissue and lipid source of key odorants would be preliminarily identified. Based on the analysis of lipid metabolomics during the crab steaming, the relationship among lipid fraction contents, non-volatile metabolic products of lipids and key odorant contents will be further studied and to deduce the possible pathways of key odorant formation by the lipids degradation and oxidation. Then, these possible pathways will be validated by the comprehensive analysis of the thermal degradation and oxidation for the following lipids, including different purified lipid fractions from crabs, artificially modified lipids (TG or PL with the specific fatty acids) and pure fatty acids. Furthermore, the function of the specific lipid fraction for odorant formation will be confirmed by the feeding E.sinensis experiment with supplemented those lipids in their diets. Finally, the formation mechanism of key odorants would be elucidated for E.sinensis by the above results. Therefore, the expected outcomes of this project could be not only improve our understanding of formation mechanism of lipid-sourced odorants for meat and their products, but also provide the basic information for the quality improvement of cultured E.sinensis and the development of crab flavor-simulated foods in the future.

中华绒螯蟹(简称河蟹)香气独特、味道鲜美，深受消费者青睐，初步研究发现河蟹蒸煮后由脂质降解生成的醛类等为其主要香气物质，但是有关河蟹香气物质的形成机制尚未明晰。本项目首先通过研究河蟹蒸煮前后可食组织中脂类及脂肪酸的含量变化，探讨蒸煮过程中关键香气物质溢出与脂类构成变化之间的关系，初步确定河蟹关键香气物质的主要来源组织和脂质；进一步通过河蟹蒸煮过程中的脂质代谢组学研究，全面分析脂类组成、非挥发性脂类降解产物和香气物质三者之间的关系，推断脂类来源关键香气物质的可能形成路径；在此基础上，通过系统研究河蟹组织中分离纯化的脂质成分、人工合成的特定脂质成分及脂肪酸纯品在加热过程中的氧化降解特性，确定河蟹关键香气物质的来源脂质成分及脂肪酸，以解析和验证河蟹脂类来源关键香气物质的形成机制。本研究结果不仅有助于深入理解脂质来源香气物质的形成机制，且对调控河蟹风味品质和开发蟹味模拟食品等具有重要的现实意义。

中华绒螯蟹(简称河蟹)是我国特色水产品，独特的香气赋予其很高的经济价值，因此，深受消费者青睐，市场需求巨大。蟹肉、肝胰脏和性腺是河蟹的三个主要可食部位，其中肝胰腺和性腺(卵巢)中脂肪含量较高，蒸煮时具有独特的香味。. 在本项目资助下，项目组成员在前期研究基础上，研究河蟹蒸煮前后可食组织中脂类及脂肪酸的含量变化、蒸煮过程中的脂质代谢组学，推断脂类来源关键香气物质的可能形成路径，通过系统研究河蟹组织中分离纯化的脂质成分、人工合成的特定脂质成分及脂肪酸纯品在加热过程中的氧化降解特性，以探讨脂类来源关键香气物质的形成机制。. 通过对蒸煮后河蟹各可食组织及整体中生成的香气物质进行定性、定量分析，采用气相色谱-嗅闻法(GC-O)判定香气物质的气味活性值，从中筛选并确定了河蟹的关键香气物质。采用棒状薄层色谱法分析了蒸煮前后河蟹各可食组织及整体中的脂质构成，通过柱层析法分离提取不同类型脂质、通过阴离子交换树脂法提取游离脂肪酸，采用GC法测定了各脂质中脂肪酸及游离脂肪酸的构成。比较蒸煮前后河蟹不同可食组织及整体中脂质氧化降解及香气物质生成规律，分析两者间的相关性，初步确定了河蟹关键香气物质的主要来源组织及脂质。构建并研究了香气主要来源组织的不同热反应体系，确定了河蟹关键香气物质的生成规律。本项目发表了分别被SCI和EI收录的标注致谢论文5篇和6篇，申请发明专利4项，培养博硕研究生10人，圆满完成了项目申报书的研究内容，达到了预期研究目的。. 本研究结果不仅有助于深入理解脂质来源香气物质的形成机制，且对调控河蟹风味品质和开发蟹味模拟食品等具有重要的现实意义。