海参蛋白肽粉吸湿诱导关键异味物质形成机制研究

Sea cucumber peptide powder is high in nutrition and digestible, and is commonly used in the products development with high quality and value in the form of nutrition compatibility as basic material powder. However, during processing and storage the peptide powder has metamorphosing phenomenon such as moisture absorption, sticky, getting agglomeration, and off-flavor forming. It is a hot topic in the research of foodborne peptide powder that has puzzled researchers for many years, as well as an important scientific problem that needed to be settled. But there is no research on the key off-flavor formation mechanism of peptide powder induced by moisture absorption. The sea cucumber peptide powder will be used for the research in this project. Dynamic vapour sorption (DVS) and low-field nuclear magnetic resonance (LF-NMR) technology will be used to reveal the water migration rules during the hygroscopic process. The full two-dimensional gas chromatography-time of flight mass spectrometry (GC×GC-TOF-MS) and gas chromatography-olfactometry (GC-O) technology will be used to establish the off-flavor fingerprint chromatography to reveal the relationship between moisture absorption and the key off-flavor formation. Furthermore, combining microbial genomics, metagenomics, chemometrics, and bioinformatics, the key off-flavor substance formation path of the sea cucumber peptide powder induced by moisture absorption will be revealed by studying the formation rule of key off-flavor precursor and intermediate products during moisture absorption of the sea cucumber peptide powder. Finally, the formation mechanism of key off-flavor would be elucidated for the sea cucumber peptide powder induced by moisture absorption. It will give theoretical foundation for the stability research of sea cucumber peptide powder with high quality and the application of basic material powder of foodborne peptides.

海参蛋白肽粉营养效价高、易消化吸收，常以基料粉营养配伍形式用于高质高值化系列产品开发，但在加工贮藏过程中存在吸湿、发黏、结块并伴随异味产生等品质劣变现象，这正是食源性蛋白肽粉研究领域共同面临的技术瓶颈和亟待攻克的重要科学问题，而国内外相关领域未见吸湿诱导关键异味物质形成机制研究。本项目以海参蛋白肽粉为研究对象，运用DVS动态水分吸附系统和低场核磁共振技术探究其吸湿过程中水分迁移规律，借助全二维气相色谱-飞行时间质谱和气相色谱-嗅闻-质谱联用技术构建异味指纹图谱，解析吸湿过程中水分迁移与关键异味物质生成的关系；通过研究海参蛋白肽粉吸湿诱导的关键异味前体物及中间产物生成规律，结合微生物基因组学、宏基因组学、化学计量学和生物信息学等手段，揭示关键异味物质生成途径，从而阐明海参蛋白肽粉吸湿诱导关键异味物质的形成机制。本研究为高品质海参蛋白肽粉稳态化研究与食源性蛋白肽基料粉加工应用奠定理论基础。

海参蛋白肽粉营养价值高、易消化吸收，常以基料粉营养配伍形式用于高质高值化系列产品开发，但在加工贮藏过程中存在吸湿、发黏、结块并伴随异味产生等品质劣变现象。本项目以海参蛋白肽粉为研究对象，分析了不同贮藏条件下海参蛋白肽粉的水分迁移规律；探究了海参蛋白肽粉的吸湿行为诱导其挥发性物质的含量变化规律；综合运用光谱学和波谱学等多种检测手段分析了高吸湿贮藏环境中吸湿行为对其结构以及异味中间产物的影响；基于16S rDNA扩增子测序技术进一步探究了海参蛋白肽粉吸湿行为与其微生物群落的关系；利用HS-GC-IMS技术构建了海参蛋白肽粉典型吸湿行为的异味特征指纹图谱，对海参蛋白肽粉吸湿与异味生成的机制关系进行研究探讨。本研究发现贮藏初期环境中的水蒸气逐渐吸附至肽粉中，主要以结合水和吸附水的形式存在，肽粉内部结合水和吸附水之间会发生迁移和相互转换；随着贮藏时间的延长，水蒸气主要转化为结合水，而部分吸附水也逐渐向结合水迁移，直到结合水达到吸附饱和，吸附水和间隙水缓慢增加后也随之饱和；高吸湿贮藏环境（25°C/75%RH）中的海参蛋白肽粉产生的挥发性化合物包括醛类、酮类、吡嗪类等异味物质。顺式氧化香芹酮被证实为(Z)-3,5-二甲基-2-(1-丙烯基)-吡嗪的异味前体物质。酯化反应导致醛类化合物含量增高；高吸湿贮藏环境中肽分子的β-折叠构象逐渐向无规卷曲和α-螺旋构象转化；贮藏90天后，海参蛋白肽粉的游离氨基酸如组氨酸、色氨酸的含量降低；吸湿行为导致厚壁菌、变形菌和拟杆菌的聚集，而干燥环境可以通过抑制厚壁菌和变形菌的生长有效降低海参蛋白肽粉的变质。并且吸湿行为可诱导其挥发性物质的改变，通过构建海参蛋白肽粉的挥发性物质特征指纹图谱，发现无菌和干燥环境可以有效控制海参蛋白肽粉吸湿行为对其挥发性物质的影响，而异味的形成机制主要与美拉德反应、酯化反应、脂肪氧化和微生物代谢有关。本项目不仅为海参蛋白肽粉的贮藏包装研究提供了新的思路，也为食源性蛋白肽的贮藏研究提供科学依据。