低温保鲜淡水鱼质构变化的分子机制研究

Texture is an important indicator for muscle quality. Deterioration of fillet texture during chill storage usually occurs in different degrees. Degradation of protein is thought to be mainly responsible for textural quality alteration of fish flesh. Fish muscle usually contains abundant endogenous enzymes which are closely related to muscle protein degradation. However, it is unclear for the specific role and the involved mechanism of endogenous enzymes in textural change of chilled freshwater fish flesh. In the present study, the freshwater fish-grass carp being used as material, the changes in protein during super-chilling or ice-storage and its relationship with texture quality will be investigated by proteomic method. On the basis of elucidation of the key protein components reponsible for textural deterioration, the changes in activies of endogenous enzyme and its inhibitors, as well as their contribution to degradation of fish protein and its influence on the texture quality of fish flesh during chill storage will be studied in order to elucidate the key endogenous enzymes reponsible for degradation of texture associated proteins and their action mechanism. The relationship between endogenous enzyme-mediated protein degradation with chilled fillet quality at protein level will be revealed through comprehensive application of proteomics, protein chemistry, enzymology, histological methods.This research will contribute to the clarification of biochemical mechanism underlying the quality change for fillet druing chill storage. And it is also of great significance for enriching the theory of low-temperature preservation for aquatic products and effective control of the quality for chilled fish flesh.

质构是评价肉品品质的重要指标。鱼肉在低温保鲜过程中质构常会发生不同程度的劣化，蛋白降解是引起鱼肉质构变化的重要原因。鱼肉中含有丰富的蛋白降解酶类，目前对于内源酶在低温保鲜淡水鱼品质变化中的作用和机制尚缺乏明确的认识。本研究以大宗淡水鱼类草鱼等为研究对象，基于蛋白质组学方法探讨淡水鱼微冻和冰藏保鲜过程中蛋白质变化及与鱼肉品质间的关系，明确参与鱼肉质构劣化的关键蛋白组分；在此基础上，通过分析内源酶及其抑制剂的活性变化和对鱼肉蛋白组分的降解作用及对鱼肉质构品质的影响研究，探讨参与鱼肉质构劣化相关蛋白降解的关键内源酶及其作用机制；综合应用蛋白质组学、蛋白质化学、酶学、组织形态学等相关技术手段和方法，从蛋白质水平初步揭示内源酶介导的蛋白降解与低温保鲜鱼肉品质间的关系。本研究有助于阐明低温保鲜鱼肉品质变化的生化机制，同时对丰富水产品低温保鲜理论和有效控制保鲜鱼肉品质具有非常重要的意义。

本项目针对冷藏鱼肉质构劣化问题重点研究了淡水鱼低温保鲜过程中内源蛋白酶分布、活性变化及对鱼肉蛋白组分的降解作用和对肌肉组织结构及质构品质的影响，探明了草鱼肉低温贮藏过程中肌原纤维蛋白、骨架蛋白、胶原蛋白等不同蛋白组分的变化规律，明确了肌原纤维蛋白、胶原蛋白和骨架蛋白的降解和解离的是造成鱼肉质构劣化的主导因素；从对内源蛋白酶活性变化分析与应用纯酶组分和添加酶特异性抑制剂两方面研究了不同内源蛋白酶对不同蛋白组分的降解作用及与鱼肉质构品质间的关系，阐述了内源蛋白酶在鱼肉贮藏过程中作用的先后顺序机制，确定了不同內源蛋白酶组分在冷藏草鱼肉质构劣化中的相对作用，组织蛋白酶B和L在整个贮藏阶段发挥作用，钙激活蛋白酶仅在前24h起作用，而胶原蛋白酶则主要对鱼片贮藏后期质构劣化有贡献，初步揭示了冷藏保鲜鱼肉质构劣化的分子机制；在此基础上研究了天然提取物、可食用添加剂对不同鱼肉內源蛋白酶的抑制作用及对冷鲜鱼肉质构品质的影响，开发了基于内源蛋白酶抑制的冷鲜鱼肉品质控制技术。本项目研究有助于阐明冷鲜鱼肉贮藏过程中品质变化的生化机制，为低温保鲜淡水鱼品质控制提供了理论基础和应用依据。