羟自由基氧化体系对大黄鱼肌原纤维蛋白结构的影响

Effect of Hydroxyl Radical Oxidation System on Structure of Myofibrillar Protein in Cultured Pseudosciaena crocea

本文采用羟自由基氧化体系模拟氧化,研究在不同氧化时间(1、3、5 h)和不同的H_2O_2浓度(0、0.1、1、5、10、20 mmol/L)下,大黄鱼肌原纤维蛋白的羰基含量、表面疏水性、活性疏基含量、溶解度和持水性五个指标的变化。结果表明:羟自由基氧化会引起大黄鱼肌原纤维蛋白(Myofibrillar protein isolate,MPI)结构发生改变,随着浓度和时间的增加,羰基含量总体上升,表面疏水性稍有升高,氧化时间不变(1 h)时,随着H_2O_2浓度的增加,活性巯基含量呈降低趋势。氧化时间为1、3 h时,经H_2O_2处理后,溶解度明显呈下降趋势,在5 h时,其溶解度呈先上升后下降的趋势,氧化时间为5 h时,随着H_2O_2浓度的增加,蛋白持水能力下降。SDS凝胶电泳分析发现,蛋白质氧化会导致蛋白质分子间发生交联。这些变化说明,自由基氧化体系对大黄鱼肌原纤维蛋白的结构有非常重要的影响。

In this paper,hydroxyl radical oxidation system was used to simulate oxidation,the changes carbonyl content,surface hydrophobicity,active hydrophobic content,solubility and water retention of myofibrillar protein in cultured Pseudosciaena crocea under different oxidation time(1,3,5 h) and oxidant concentrations(0,0.1,1,5,10,20 mmol/L H2O2) were explored.The results showed that hydroxyl radical oxidation system could cause MPI structure changes in Pseudosciaena crocea.With the increase of concentration and time,the carbonyl content increased and the surface hydrophilicity increased slightly.When the oxidation time was 1 h,the contents of active sulfhydryl group decreased with the increasing of H2O2 concentration.When the oxidation time was 1,3 h,the solubility decreased obviously after H2O2 treatment.At 5 h,the solubility increased first and then decreased.When the oxidation time was 5 h,the water holding capacity decreased with the increasing of H2O2 concentration.SDS gel electrophoresis revealed that protein oxidation could lead to cross-linking between proteins.These changes indicated that the free radical oxidation system had a very important effect on the structure of myofibrillar protein in Pseudosciaena crocea.