羟自由基氧化对鲢鱼肌原纤维蛋白凝胶特性的影响

采用含不同浓度H₂O₂(0.0～10.0 mmol/L)的Fenton体系(H₂O₂-VC-FeCl₃)模拟氧化应激环境对鲢鱼肌原纤维蛋白进行氧化，测定蛋白的巯基含量，以及蛋白凝胶的凝胶强度、白度、持水性、水分分布状态及微观结构，探究氧化度对蛋白凝胶特性的影响。结果表明：随着H₂O₂浓度的增加，蛋白的总巯基含量和白度、持水性呈先升高后降低的趋势。当体系中H₂O₂浓度较低(0.1～0.5 mmol/L)时，蛋白凝胶强度增大，白度得到改善；凝胶的三维结构孔洞的面积较小，且分布较为均匀，凝胶的持水力有所增强。但是当体系中的H₂O₂浓度较高(5.0～10.0 mmol/L)时，蛋白凝胶的白度下降，凝胶结构的有序性降低，孔洞面积变大，分布变得不均匀，凝胶的持水力下降，凝胶品质发生劣变。因此，适度氧化(0.1～0.5 mmol/L H₂O...

Effect of Hydroxyl Radical-Induced Oxidation on Gel Properties of Silver Carp Myofibrillar Protein

In this study, silver carp myofibrillar protein (MP) was oxidized with different concentrations of H2O2 (0.0‒10.0 mmol/L) in the Fenton system (H2O2-VC-FeCl3) to explore the effect of oxidation degree on protein gel formation and gel properties. The sulfhydryl content of MP was measured. The gel strength, whiteness, water-holding capacity, moisture distribution and microstructure of MP gels were determined. The results showed that as H2O2 concentration increased, the total sulfhydryl content, whiteness and water-holding capacity of MP increased first and then decreased. When the H2O2 concentration in the system was low (0.1‒0.5 mmol/L), the gel strength and whiteness were both improved. The area of pores in the three dimensional gel structure became smaller, the distribution became more uniform, and the water-holding capacity of MP gels was enhanced. However, at high H2O2 concentration (5.0‒10.0 mmol/L), the gel whiteness decreased, and the gel structure became disordered, the pore area became larger, the pore distribution became nonuniform, and the water-holding capacity decreased, indicating a deterioration in gel quality. Therefore, appropriate oxidation (0.1‒0.5 mmol/L H2O2) contributed to the improved properties of protein gels. The analysis of the peptide composition by liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed that the major oxidation regions of MP by hydroxyl radicals were the heavy chain of myosin and actin. Moreover, methionine, cysteine, aspartic acid and glutamic acid were recognized as the high-frequency oxidation sites of MP.