盐浓度对欧洲鳗肌原纤维蛋白理化性质和凝胶形成性能的影响

Effects of NaCl Concentration on Physicochemical Properties and Gelforming Ability of Myofibrillar Protein from European Eel

为探究盐浓度对欧洲鳗肌原纤维蛋白热诱导凝胶形成性能的影响,测定了蛋白的浊度、表面疏水性和活性巯基的变化,考察了0.1、0.3、0.5 mol/L的NaCl浓度下的肌原纤维蛋白热诱导凝胶的性质。结果表明,欧洲鳗肌原纤维蛋白的浊度、表面疏水性和活性巯基分别在30、35和40℃开始增加。随着NaCl浓度的增加,肌原纤维蛋白的热吸收峰温度降低,而储能模量和损耗模量增加。0.5 mol/L NaCl溶解的欧洲鳗肌原纤维蛋白热诱导凝胶破断强度为98.81 g,高于低浓度NaCl溶解的蛋白热诱导凝胶。电泳结果表明,增加NaCl浓度会促进肌球蛋白重链和肌动蛋白的相互作用。根据傅里叶变换红外光谱和扫描电镜结果,发现0.5 mol/L NaCl溶解的肌原纤维蛋白热诱导凝胶具有最高的酰胺Ⅱ/酰胺Ⅰ强度比和最致密的网络结构。研究结果表明欧洲鳗肌原纤维蛋白在35℃时开始变性,提高NaCl浓度可以增强热诱导蛋白凝胶的强度和网络结构致密度,将为利用盐浓度和温度调控鳗鱼加热调理产品提供理论指导。

The effect of NaCl concentration on heat-induced gel forming ability of myofibrillar protein from European eel muscle was studied.The turbidity,surface hydrophobicity and reactive sulfhydryl groups of the protein was measured.Meanwhile,the properties of heat-induced gel of myofibrillar protein at 0.1,0.3 and 0.5 mol/L NaCl concentration were investigated.It was found that turbidity,surface hydrophobicity and reactive sulfhydryl groups began to increase at 30,35 and 40℃,respectively.With the increase of NaCl concentration,the temperature of endothermic peaks of myofibrillar protein decreased,while the storage modulus and loss modulus increased.The breaking strength of heat-induced protein gel prepared with 0.5 mol/L NaCl was 98.81 g,which was higher than that of the heat-induced protein gel prepared with low NaCl concentration.The increased NaCl concentration could promote the interaction between myosin heavy chain and actin according to the electrophoresis analysis.Based on the results of Fourier transform infrared spectra and scanning electron microscopy,heat-induced myofibrillar protein gel with 0.5 mol/L NaCl had a highest Amide II/Amide I intensity ratio and densest network.The result of this study suggested that myofibrillar protein from European eel muscle was prone to denature at above 35℃,and the gel strength and network structure of heat-induced myofibrillar protein gels could be improved by increasing the addition of NaCl.The obtained results will provide theoretical guidance for controlling the quality of eel based heat-processed food by using salt concentration and temperature.