低场核磁共振研究pH值对兔肌球蛋白热凝胶特性的影响  

Effect of pH on Gelation Properties of Rabbit Myosin

作　　者：吴烨[1] 许柯[1] 徐幸莲[1] 牛蕾[1] 

机构地区：[1]南京农业大学教育部肉品加工与质量控制重点实验室,江苏南京210095

出　　处：《食品科学》2010年第9期6-11,共6页Food Science

基　　金：国家自然科学基金项目(30771526)

摘　　要：研究pH值对兔骨骼肌肌球蛋白热诱导凝胶保水性以及水分移动性的影响。运用低场核磁共振测定肌球蛋白凝胶中水的T2弛豫时间,同时测量保水性和硬度并观察凝胶超微结构。核磁共振结果拟合后发现,对应不可移动水和自由水的T22和T23弛豫时间随着pH值升高而降低,说明水分的移动性随着肌球蛋白所带负电荷数目增加而减弱;主成分分析结果发现,T22和T23弛豫时间与保水性、硬度和凝胶孔径有较强的相关性;位于等电点附近的样品在样品评分图上与其他样品有显著不同。肌球蛋白的蛋白质分子表面电荷数量和分布影响了蛋白质分子卷曲和伸展的情况,对最终凝胶保水性、硬度和网孔直径有很大影响,而T2弛豫时间则能很好的反映这种变化趋势。In order to investigate the effect of pH on water-holding capacity and water mobility of heat-induced gelation from rabbit myosin,gelation properties of rabbit myosin were characterized through determining relaxation time（T2） of water using low-field nuclear magnetic resonance（NMR）,and water-holding capacity（WHC）,hardness and ultra microstructure of the gel.NMR results indicated that relaxation time for immobile water（T22） and relaxation time for free water（T23） exhibited a decrease as the increase of pH,which suggested that the slow water mobility resulted from the increased number of negative charge in myosin.Principal component analysis results revealed that T22 and T23 relaxation time had strong correlation with WHC,hardness and diameter of the gel.A significant difference was observed between samples near pI points and other samples.Moreover,the number and distribution of surface charge exhibited an effect on curling and stretching of myosin molecules,and finally affected WHC,hardness and mesh diameter of the gel,while T2 relaxation time could reflect this tendency well.

关 键 词：肌球蛋白 凝胶 低场核磁共振 PH值 保水性 

分 类 号：TS201.21[轻工技术与工程—食品科学]