脂肪氧化对肌原纤维蛋白氧化及其结构和功能性质的影响

通过建立不同氧化程度的脂肪促进肌原纤维蛋白氧化模型，研究脂肪氧化对肌原纤维蛋白氧化的促进作用 及其对蛋白氧化后性质和结构的影响。结果表明：脂肪氧化产生的自由基可以促进蛋白质发生氧化反应，随着脂肪 氧化程度的增加，肌原纤维蛋白的羰基含量、巯基含量和二酪氨酸含量发生显著变化（P＜0.05），当硫代巴比妥 酸反应产物含量为2.5 mg/kg时，羰基含量、巯基含量和二酪氨酸含量分别为4.12、81.33 nmol/mg pro、563.36 AU， 表明蛋白质的氧化程度和表面疏水性逐渐升高，流变学特性储能模量和损失模量也随之降低，稳定的α-螺旋和β-折 叠部分遭到破坏，转变成不稳定的β-转角和无规卷曲，肌原纤维蛋白的结构和功能特性都随着脂肪氧化程度的增加 发生变化。

Effect of Lipid Oxidation on Myofibrillar Protein Oxidation,Structure and Functional Characteristics

The promotion effect of fat oxidation on myofibrillar protein oxidation was studied by establishing a protein oxidation model with different degrees of lipid oxidation, and its influence on the properties and structural characteristics of myofibrillar protein was also explored. The results showed that free radicals produced by fat oxidation could promote protein oxidation. With the increase of fat oxidation, the degree of myofibrillar protein oxidation showed a significant increase as indicated by significant changes in the contents of carbonyl, sulfhydryl and di-tyrosine (P < 0.05), whose values were 4.12, 81.33 nmol/mg, and 563.36 AU, respectively when the thiobarbituric acid reactive substances (TBARS) value was 2.5 mg/kg. As a result, the surface hydrophobicity of the protein gradually rose, whereas its rheological properties such as storage modulus and loss modulus decreased. The stable secondary structures of α-helix and β-fold were partially destroyed and transformed into unstable β-turn and random coil. Thus, the structure and functional characteristics of myofibrillar protein showed significant changes with increasing degree of oxidation.