基于组学策略研究多酚单体对淡水鱼冷藏保鲜过程中蛋白质降解与脂质氧化的抑制作用及其机理

China has large freshwater fish production in the world. During the process of storage and preservation of freshwater fish, it often became spoiled and corrupted due to the degradation of proteins and oxidation of lipids. This phenomenon has seriously affected the quality of freshwater fish and its’ applicability as raw materials. As one kind of bio-preservatives, polyphenol can effectively inhibit or slow down the activity of microbial, protein degradation and lipid oxidation, which could decrease the quality of fish. Currently, it not clear about the mechanism of polyphenols which could inhibit the protein degradation and lipid oxidation. In this project, the proteomics approach was used to detect the degradation of protein, and screen the key protein during the process of grass carp cold storage with the addition of polyphenol monomer. Meanwhile, the metabolomics method was used to study the metabolic pathways of small molecules in freshwater fish during cold storage, and find the representative metabolic substances of lipid oxidation and protein degradation. Furthermore, the interactions between the polyphenol monomers and myofibrillar protein, or the key endogenous enzymes related to lipid oxidation was investigated using a variety of spectroscopic methods and molecular docking techniques. Finally, the inhibition mechanism of polyphenol monomer effect on the freshwater fish was explored by the combination of omics, molecular biology and molecular docking with data mining methods. This project could provide detailed theoretical basis for the preservation of freshwater fish.

我国是淡水鱼生产大国。在贮藏与保鲜过程中，淡水鱼经常由于蛋白质容易降解和脂质易氧化而产生腐败变质现象，严重制约了其品质及作为加工原料的适用性。作为一种生物保鲜剂，多酚可以有效抑制或减缓微生物活动，降低蛋白质降解和脂质氧化。目前关于多酚对蛋白质降解和脂质氧化的抑制作用机理尚不明确。本项目拟以草鱼为研究对象，利用多种组学技术研究多酚对蛋白质降解和脂质氧化的抑制作用及其机理。该项目采用蛋白质组学技术对蛋白质降解规律进行检测，筛选出关键性指示蛋白；利用代谢组学研究淡水鱼冷藏保鲜过程中的小分子物质的代谢规律，寻找代表性脂质与蛋白质的代谢产物；采用多种光谱手段及分子对接技术研究多酚单体与蛋白、关键内源酶之间的相互作用；最后利用数据发掘方法整合组学、分子生物学、分子对接等相关数据，多角度剖析多酚的抑制机理，为淡水鱼的冷藏保鲜提供翔实的理论依据。

在淡水鱼贮藏与保鲜过程中，由于含水量高，内源酶活性高等原因，淡水鱼极易发生蛋白质降解和脂质易氧化而出现腐败变质的现象。天然保鲜剂多酚可以有效抑制或减缓微生物活动，降低蛋白质降解和脂质氧化的程度，但其作用机理还尚不明确。本项目以草鱼为研究对象，利用多种组学技术研究多酚对蛋白质降解及脂质氧化的抑制作用及机理。通过采用多种光谱手段及分子对接技术研究多酚和草鱼肌球蛋白、肌原纤维蛋白之间的分子间相互作用，引起草鱼肌球蛋白或肌原纤维蛋白的荧光猝灭，形成新的复合物，从一定程度上缓解了草鱼蛋白的降解及氧化程度。研究了多酚对关键内源酶的抑制及其作用机制，结果表明多酚能明显抑制草鱼的关键内源酶的活性，降低了脂质氧化的程度。定量蛋白组学结果表明在多酚的作用下，草鱼结构蛋白的降解程度显著降低。通过脂质代谢组学分析多酚在冷藏过程中对草鱼肌肉脂类化合物组成和含量变化的影响，揭示贮藏过程中脂质的变化规律，发现多酚对PC、PE、PG等甘油磷脂的水解均有一定的抑制作用。本项目整合组学、分子生物学、分子对接等相关数据，多角度剖析多酚的抑制机理，为淡水鱼冷藏保鲜的相关研究提供了翔实的理论依据。