摘要
以草鱼肉为研究对象,采用芬顿反应体系(H_2O_2浓度分别为0.1、1.0、5.0、10.0 mmol/L)产生不同浓度·OH对其肌原纤维蛋白进行模拟氧化,研究·OH氧化对草鱼肌原纤维蛋白结构及凝胶性质的影响。结果表明,氧化使肌原纤维蛋白羰基含量显著增加(P<0.05),当氧化剂H_2O_2的浓度为10.0 mmol/L时,羰基含量比对照组增加了111.35%;随着H_2O_2浓度的提高,肌原纤维蛋白总巯基、活性巯基、游离氨基含量显著下降(P<0.05);二聚酪氨酸水平和表面疏水性显著增加(P<0.05)。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析表明氧化使蛋白质分子间发生交联和聚集,产生了分子质量大于200 ku的蛋白聚集体。可见,·OH氧化使草鱼肌原纤维蛋白中巯基、酪氨酸、色氨酸等氨基酸残基发生了显著氧化修饰,蛋白质分子产生了交联和聚集,蛋白质构象发生了显著变化。此外,氧化可进一步影响肌原纤维蛋白的凝胶性质,使其凝胶网络结构变疏松、凝胶孔隙增大,凝胶中部分不易流动水转变为自由水,最终导致凝胶强度和凝胶持水性显著降低。
In this paper, myofbrillar protein from grass carp was artifcially oxidized in hydroxyl radical-generating system with H2O2 concentrations of 0.1, 1.0, 5.0 and 10.0 mmol/L, and the effect of oxidization on the structural characteristics and gel properties of myofbrillar protein was investigated. The results showed that the carbonyl content increased signifcantly （P 〈 0.05） after oxidization by 111.35% compared to the initial value when the concentration of H2O2 was 10.0 mmol/L. With the increase in H2O2 concentration, the total thiol group level, free thiol group level, and free amine content decreased signifcantly （P 〈 0.05）, while bityrosine content and surface hydrophobicity increased signifcantly （P 〈 0.05）. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE） result showed that hydroxyl radical oxidation could induce the crosslinking and aggregation of protein molecules, thereby forming aggregates with molecular mass higher than 200 ku. The above results indicated that the thiol group, tyrosine and tryptophane residues of myofbrillar protein were modifed after hydroxyl radical oxidation, thus leading to a signifcant change in protein structure. In addition, the gel properties of myofbrillar protein were also in？uenced by oxidation, the network structure of the gel was damaged, and the portable water in the gel was converted to free water. These changes fnally induced apparent decreases in the gel strength and water-holding capacity.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2017年第21期30-37,共8页
Food Science
基金
国家自然科学基金面上项目(31771999)
中国博士后科学基金项目(2015M582143)
"十二五"国家科技支撑计划项目(2015BAD17B03)
辽宁省教育厅重点实验室基础研究项目(LZ2014047)
关键词
草鱼
肌原纤维蛋白
蛋白质氧化
结构特征
凝胶性质
grass carp （Ctenopharyngodon idellus）
myofbrillar protein
protein oxidation
structural characteristics
gel properties
