NaCl对大菱鲆肌原纤维蛋白特性的影响

Effect of NaCl on Properties of Myofibrillar Protein from Turbot(Scophthalmus maximus)

以大菱鲆肌原纤维蛋白为对象,考察不同NaCl浓度(0.1、0.2、0.3、0.4、0.5、0.6 mol/L)下肌原纤维蛋白的溶解度、乳化性、化学作用力(离子键、氢键、疏水相互作用)、巯基的变化,并对其二级结构以及流变学特性进行测定。结果表明,随着NaCl浓度的增加,大菱鲆肌原纤维蛋白的溶解度、乳化活性、乳化稳定性、总巯基和活性巯基含量均不断增加;离子键、氢键呈先增加后下降趋势,疏水性相互作用呈先下降后增加的趋势;蛋白质二级结构呈现由螺旋向折叠转化的趋势,其他二级结构无明显变化;肌原纤维蛋白储能模量(G’)不断增加,其中以NaCl浓度0.6 mol/L的实验组储能模量最大。综上所述,NaCl浓度为0.6 mol/L时,大菱鲆肌原纤维蛋白的各项指标良好。

The objective of this study was to evaluate the effect of different concentrations of NaCl(0.1,0.2,0.3,0.4,0.5,and 0.6 mol/L)on the properties of turbot myofibrillar protein(MP).MP was extracted and its solubility,emulsifying properties,chemical interactions(ionic bonds,hydrogen bonds and hydrophobic interactions)and sulfydryl contents,secondary structures and rheological properties were measured.The results showed that solubility,emulsifying activity index(EAI),emulsion stability index(ESI),active and total sulfydryl contents increased with the increase in NaCl concentration.Meanwhile,ionic and hydrogen bonds first increased and then decreased,whereas hydrophobic interactions first decreased and then increased.The secondary structures of MP tended to transit from helix to sheet with no significant change being observed for the other secondary structures;storage modulus(G’)was increased,with the highest value being observed at a NaCl concentration of 0.6 mol/L.In summary,0.6 mol/L NaCl was optimal for improving the properties of turbot myofibrillar protein.