Effects of egg white (EW) modified by different concentrations (0.2%, 0.4%, 0.6%, 0.8% w/w) of tea polyphenols (TP) on physicochemical properties and microstructure properties of surimi gel were investigated. FTIR analysis showed that TP modification changed the secondary structure of EW proteins, reduced α-helix content but increased the content of β-folding. The TP-modified EW showed significant effects (P < 0.05) in increasing the breaking force and deformation of surimi and resulted in the formation of a stronger network in surimi gel with greater water-holding capacity, as indicated by a lowered expressible moisture content, decreased solubility and increased storage modulus (G′) and loss modulus (G″) by dynamic viscoelastic measurement. Protein pattern analysis suggested that the TP-modified EW might contribute to the decrease in the myosin heavy chain (MHC) band intensity of surimi through cross-linking with surimi proteins, which might further increase the superior setting phenomenon of surimi gel. Moreover, a finer and more ordered network of the gel was observed. Therefore, TP-modified EW is efficient in improving the properties of surimi gel, and for the best effect, a concentration of 0.6% is recommended.

中文翻译：

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茶多酚改性蛋白处理鱼糜理化性质及微观结构

研究了不同浓度（0.2%、0.4%、0.6%、0.8% w/w）的茶多酚（TP）改性的蛋清（EW）对鱼糜凝胶理化性质和微观结构性质的影响。FTIR分析表明，TP修饰改变了EW蛋白的二级结构，降低了α-螺旋的含量，但增加了β-折叠的含量。TP 改性的 EW 在增加鱼糜的断裂力和变形方面表现出显着效果（P < 0.05），并导致鱼糜凝胶中形成更强的网络，具有更大的持水能力，如可表达的水分含量降低所示，通过动态粘弹性测量降低溶解度并增加储能模量 (G') 和损耗模量 (G")。蛋白质模式分析表明，TP修饰的EW可能通过与鱼糜蛋白的交联导致鱼糜的肌球蛋白重链（MHC）带强度降低，这可能进一步增加鱼糜凝胶的优越凝固现象。此外，观察到更精细和更有序的凝胶网络。因此，TP 改性 EW 可有效提高鱼糜凝胶的性能，为获得最佳效果，建议使用 0.6% 的浓度。