以罗非鱼肉为原料,提取肌球蛋白,试验了不同盐浓度(1、50、150、600 mmol/L NaCl)下,肌球蛋白(2 mg/mL)体系热处理过程中溶解度、浊度、表面疏水性、巯基的变化,在此基础上制备热诱导凝胶(20 mg/mL),探讨不同盐浓度下肌球蛋白热凝胶的形成及机理。结果表明,随着盐浓度的增大,肌球蛋白的溶解度逐渐增加,浊度减小,表面疏水性和巯基含量增加;随着热处理(20~80 ℃,1 ℃/min)的进行,肌球蛋白的溶解度下降(p<0.05),表面疏水性显著增大(p<0.05),巯基含量减少,分子逐渐变性聚集;热诱导体系的动态弹性模量随盐浓度的增加而增大,维持肌球蛋白凝胶三维网状结构的主要作用力是疏水相互作用、二硫键和非二硫共价键,高盐条件下肌球蛋白热诱导凝胶的网状结构较稳定。研究结果为水产蛋白制品的加工提供了理论基础。
Myosin was extracted from tilapia muscle, the changes of turbidity, solubility, surface hydrophobicity and sulfhydryl content of myosin under different salt concentration (1, 50,150, 600 mmol/L NaCl) were investigated. The heat-induced myosin gel was prepared and the formation and mechanism of thermal gel was discussed. Results showed that with the increasing of ionic strength, solubility of myosin gradually increased and turbidity decreased with the increasing of the surface hydrophobicity and -SH content. The solubility showed a significant downward (p<0.05), while the surface hydrophobicity was increased (p<0.05) and sulfhydryl content was decreased with heat treatment from 20 to 80 ℃ at 1 ℃/min., which indicated thermal denaturation and aggregation of myosin happened. Heat-induced dynamic elastic modulus of myosin dispersion increased with the increasing of salt concentration. Main force of three-dimensional network structure stabilized gel structure was hydrophobic interaction, disulfide bonds and non-disulfide covalent bond. Myosin gelation network structure is more stable under high ionic strength condition.