College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Fisheries Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan 430207, China.
Int J Biol Macromol. 2020 Nov 1;162:1442-1452. doi: 10.1016/j.ijbiomac.2020.08.052. Epub 2020 Aug 8.
Protein oxidation is a critical process in the deterioration and spoilage of fish and related commodities during processing and storage. In this study, the hydroxyl radical generation system (HRGS) was used to simulate the effect of oxidation on the functional, conformational and gelling properties of topmouth culter (Culter alburnus) myofibrillar proteins (MP). Additionally, the effects of oxidation on the gel-forming abilities of MP were also systematically analyzed from the perspective of intermolecular interaction forces. Oxidation was shown to decrease the total sulfhydryl content, increase the surface hydrophobicity, and induce conformational changes in MP. Rheological analysis showed that oxidation reduced the gel strength. Water holding capacity (WHC) and low-field nuclear magnetic resonance (LF-NMR) analyses showed that low oxidation could enhance water binding of protein matrix, while high-degree oxidation could substantially reduce the gelling properties of MP. The selective solubility of MP gel proved that oxidation could reduce the content of ionic and hydrogen bonds and increase hydrophobic interactions. All the results indicate that oxidation could alter the intermolecular interactions between protein-protein and protein-water molecules, due to irregular unfolding and inhibition of the cross-linking of amino acid side chains, leading to reduction in the quality and function of fish and related products.
蛋白质氧化是鱼类及其相关制品在加工和贮藏过程中变质和腐败的关键过程。在本研究中，采用羟自由基生成体系（HRGS）模拟氧化对翘嘴红鲌肌原纤维蛋白（MP）功能、构象和凝胶特性的影响。此外，还从分子间相互作用力的角度系统分析了氧化对 MP 形成凝胶能力的影响。结果表明，氧化降低了巯基含量，增加了表面疏水性，并诱导 MP 构象发生变化。流变分析表明，氧化降低了凝胶强度。持水能力（WHC）和低场核磁共振（LF-NMR）分析表明，低氧化程度可以增强蛋白质基质的结合水能力，而高度氧化会显著降低 MP 的凝胶性能。MP 凝胶的选择性溶解度表明，氧化可以减少离子键和氢键的含量，增加疏水相互作用。所有结果表明，氧化可能会改变蛋白质-蛋白质和蛋白质-水分子之间的分子间相互作用，这是由于不规则展开和氨基酸侧链交联的抑制，导致鱼类及其相关产品的质量和功能下降。
