臭氧介导的蛋白质氧化对草鱼肌原纤维蛋白凝胶持水性的影响机制

The water-holding capacity in surimi gel is one of the most important factor that influence the quality and economic value of surimi-based products, so how to improve the gel water-holding capacity of surimi gel has always been a research focus in aquatic products processing both at home and abroad. Deodorizing by ozone is one of the key progress in the production of fresh water surimi, however, the effects of ozone on surimi protein has receive little attention, and the effects of ozone on surimi gel properties and water-holding capacity are still unclear. In this project, myofibrillar protein of grass carp will be treated by different concentration of ozone, and the oxidation effects of ozone on structure, heat-induced aggregation and gelation of myofibrillar protein will be investigated by Raman spectra, fluorescence labelled proteomics techniques, differential scanning calorimetry (DSC), dynamic light scattering (DLS), atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), confocal laser scanning microscopy (CLSM), dynamic rheometry, chemical force analysis, etc. Furthermore, the effects of ozone oxidation on the gel-water interaction will be quantitative analyzed by isotopic H/D exchange in water and the capillarity theory, the prevailing hypothesis for explaining how water is held in gels. Meanwhile, the state and distribution of water in gel will be surveyed by low field nuclear magnetic resonance spectroscopy (LF-NMR) and magnetic resonance imaging (MRI). The internal relationships among the gel structure, water-holding force and water state changes will be revealed, and the mechanism of myofibrillar protein oxidation influence the heat-induce gel water-holding capacity will be clarified. The inventions and the research results of this task will provide the theoretic guidelines and technical supports for the rational application of ozone in surimi processing and the quality improvement of surimi-based products.

凝胶持水性是决定鱼糜制品品质和经济价值的核心指标，如何改善鱼糜制品凝胶持水性一直是国内外水产加工研究的热点。臭氧脱腥是淡水鱼鱼糜生产中的常用关键步骤，但对其蛋白质氧化作用的关注较少，臭氧氧化对鱼糜蛋白质凝胶持水性的影响机制尚不明确。本项目拟以草鱼肌原纤维蛋白为对象，运用拉曼光谱、荧光标记蛋白质组学技术、DSC、DLS、AFM、SEM、TEM、CLSM、动态流变仪、化学力测定等技术研究不同臭氧处理条件对草鱼肌原纤维蛋白的氧化效应，以及臭氧氧化对肌原纤维蛋白热聚集和凝胶行为的影响规律；采用重水置换技术并借助凝胶“毛细管持水理论”，定量分析氧化对凝胶-水分相互作用的影响，结合LF-NMR、MRI技术研究凝胶中水分状态及分布情况，揭示凝胶结构特征、凝胶-水分相互作用及水分状态之间的内在联系，阐明臭氧氧化对草鱼肌原纤维蛋白凝胶持水性的影响机制，为臭氧在鱼糜工业中的应用和鱼糜制品品质改良提供理论依据。

凝胶持水性是决定鱼糜制品品质和经济价值的核心指标，如何改善鱼糜制品凝胶持水性一直是国内外水产加工研究的热点。臭氧脱腥是淡水鱼鱼糜生产中的常用关键步骤，但对其蛋白质氧化作用的关注较少，臭氧氧化对鱼糜蛋白质凝胶持水性的影响机制尚不明确。本项目以草鱼肌原纤维蛋白为对象，运用拉曼光谱、蛋白质组学等技术研究了不同浓度臭氧水漂洗处理对草鱼鱼糜肌原纤维蛋白的氧化效应，揭示了臭氧处理对草鱼肌原纤维蛋白的氧化规律。采用DSC、DLS、AFM、SEM、化学力测定等技术研究了臭氧氧化对肌原纤维蛋白热聚集和凝胶行为的影响规律，明确了适量浓度臭氧水漂洗引起的草鱼鱼糜肌原纤维蛋白质氧化能够提高鱼糜凝胶强度和凝胶持水性，揭示了臭氧氧化对肌原纤维蛋白热聚集和凝胶行为的影响机制。采用重水置换技术并借助凝胶“毛细管持水理论”，定量分析了氧化对凝胶-水分相互作用的影响，结合LF-NMR、MRI技术研究凝胶中水分状态及分布情况，揭示了凝胶结构特征、凝胶-水分相互作用及水分状态之间的内在联系，以及氧化对凝胶-水分相互作用及水分状态的影响规律。项目最终阐明了臭氧氧化对草鱼肌原纤维蛋白凝胶持水性的影响机制，即臭氧介导的蛋白质氧化通过促进肌原纤维蛋白交联、改善其热聚集和凝胶行为，提高了鱼糜凝胶分子间作用力（二硫键等），使鱼糜凝胶结构更加均匀有序致密、孔洞尺寸更小。同时，氧化提高了凝胶结构的表面亲水性和毛细管作用力（即凝胶持水力），增强了凝胶中蛋白质分子与水分子相互作用，进而增加了鱼糜凝胶中不易流动水和毛细管束缚水的比例，使更多水分保持在凝胶网络结构中。研究结果为臭氧在鱼糜工业中的应用和鱼糜制品品质改良提供了理论依据。