金鲳肌球蛋白在不同处理条件下的理化性质变化

Physicochemical properties of Trachinotus ovatus myosin under different treatment conditions

通过研究漂洗、斩拌以及不同加热温度对金鲳肌球蛋白变性聚集的影响,为金鲳深加工提供理论基础。分别提取鱼肉原料、漂洗鱼糜、斩拌鱼糜肌球蛋白,并将斩拌鱼糜肌球蛋白在30、40、50、60、70和90℃分别加热30 min,测定不同处理条件下肌球蛋白浊度、溶解度、巯基、二硫键、表面疏水性等基本理化性指标,并通过红外光谱研究肌球蛋白二级结构变化,探讨金鲳肌球蛋白的变性聚集过程。结果表明,肌球蛋白浊度和溶解度基本呈相反的变化趋势,漂洗可降低肌球蛋白浊度,加热使肌球蛋白浊度增大,在90℃达到最大值;总巯基在整个加工处理过程连续下降,二硫键呈完全相反的变化趋势;漂洗和低温加热会使活性巯基显著增大,而斩拌和高温加热(60℃以上)会造成活性巯基含量减少,表面疏水性与活性巯基变化趋势相一致;漂洗后β-折叠和无规则卷曲含量略微减少,α-螺旋略增加,β-转角无明显变化,斩拌鱼糜肌球蛋白无规则卷曲结构相对含量降低4%,而β-折叠和β-转角分别增加3%和2%;加热对肌球蛋白结构影响较为复杂,在40℃加热时,α-螺旋结构解旋,主要形成β-转角和无规则卷曲,而在90℃加热时,肌球蛋白二级结构中β-折叠含量达到52. 87%。综上分析在高温加热时金鲳肌球蛋白更易主要形成β-折叠结构,并且肌球蛋白更易聚集,以期为金鲳鱼糜加工提供参考意见。

This research aims to study the effects of rinsing,grinding,and different heating temperatures on the degeneration and accumulation of myosin in gold carp,so as to provide a theoretical basis for deep processing of gold carp.The raw materials,the rinsed surimi,the ground surimi myosin were extracted respectively,and the ground surimi’s myosin was heated at 30,40,50,60,70 and 90°C for 30 min respectively to determine the muscles under different treatment conditions.The basic physicochemical indexes such as turbidity,solubility,sulfhydryl group,disulfide bond and surface hydrophobicity were determined,and the secondary structure changes of myosin were studied by infrared spectroscopy to explore the process of denaturation and aggregation of golden carp myosin.The results indicated that myosin turbidity and solubility basically showed opposite trends,and rinsing reduced myosin turbidity,and heating increased myosin turbidity,reaching a maximum at 90℃;The total sulfhydryl group decreased continuously during the entire processing process,and the disulfide bond showed a completely opposite trend;Rinse and low-temperature heating will significantly increase the active sulfhydryl group,while grinding and high-temperature heating(above 60℃)will reduce the active sulfhydryl content;After rinsing,the content ofβ-fold and random curl decreased slightly,theα-helix increased slightly,and theβ-turn had no obvious change.The relative content of the random coil structure of ground surimi was reduced by 4%,whileβ-turn angle was increased by 3%and 2%,respectively.The effect of heating on the myosin structure was complicated.The unwinding of theα-helical structure mainly formedβ-turn and irregular curl when being heated at 40℃,while being heated at 90℃,theβ-fold content in the secondary myosin structure reached 52.87%.In conclusion,golden carp myosin tends to aggregate and mainly formβ-sheet structure when being heated at high temperature.It is expected to provide references for the processing of golden carp surimi.