超高压结合热处理对肌球蛋白凝胶特性及蛋白二级结构的影响

肌球蛋白溶液先经100~600MPa压力预处理10min,处理温度20℃,后加热制备凝胶,以未超高压处理组为对照组,测定凝胶质构和保水性,采用傅里叶红外光谱法测定肌球蛋白二级结构变化,然后通过相关系数矩阵法研究肌球蛋白7种质构特性、保水性与各二级结构含量的关系.结果表明:不同超高压处理对肌球蛋白凝胶硬度的影响不显著,对凝胶保水性影响显著,随着压力升高,凝胶保水性逐渐下降.与对照组相比,100、200MPa处理的凝胶保水性无显著差异;与对照组相比,300MPa以上处理的凝胶保水性显著减少.超高压致使肌球蛋白分子结构展开,使蛋白质β-折叠等有序结构减少而β-转角等无序结构增加.从相关性分析结果得出,凝胶的黏附性、弹性、保水性与各二级结构之间存在显著的相关性.

Combined Effect of Ultra High Pressure and Heating on Gel Properties and Secondary Structure of Myosin

For the preparation of heat-induced myosin gels,myosin solution was subjected to ultra high pressure(UHP) pretreatment at 100—600 MPa and 20 ℃ before heat treatment.Heat-induced myosin gels with and without UHP pretreatment were determined for texture properties and water-holding capacity.Fourier transform infrared spectroscopy was used to examine secondary structure changes of myosin.In addition,the relationships of secondary structure contents with 7 texture parameters and water-holding capacity was analyzed using a correlation coefficient matrix.The results obtained demonstrated that UHP pressure did not significantly influence the hardness of myosin gels but had a significant negative correlation with the water-holding capacity.UHP treatments at 100 MPa and 200 MPa did not cause significant differences in the water-holding capacity of myosin gels in comparison with control groups,although UHP treatments at a pressure level higher than 300 MPa resulted in a significant reduction in the water-holding capacity of myosin gels.The molecular structure of myosin was unfolded after UHP treatment,causing a decrease in the amount of ordered structures such as β-sheet and an increase in the amount of unordered structures such as β-turn.Heat-induced myosin gels showed a significant correlation of secondary structure contents with adhesiveness,springiness and water-holding capacity.