超高压对罗非鱼肌动球蛋白物化特性的影响

Effect of Ultra-high Pressure on the Physicochemical Properties of Tilapia Actomyosin

摘要:

本文研究了超高压（100、300、500 MPa处理15、30、45 min）作用下罗非鱼肌动球蛋白物化特性的变化。结果发现，随着压力的增加和保压时间的延长，罗非鱼肌动球蛋白的溶解度降低，其中500 MPa处理45 min降至最低，为89.17%，表明超高压有利于蛋白质的聚集变性。超高压作用下罗非鱼肌动球蛋白的Ca2+-ATPase活性消失，表明肌球蛋白发生了变性。随压力与保压时间的增加，肌动球蛋白的表面疏水性增加，且300 MPa处理45 min增至最大，表明超高压作用使更多的疏水性基团暴露。随压力的增加，肌动球蛋白的总巯基含量降低，且500 MPa处理30 min降为最低值，二硫键含量升高，在300 MPa处理45 min增至最高，表明肌动球蛋白中巯基发生氧化形成了二硫键。以上物化特性的改变表明经过超高压处理的罗非鱼肌动球蛋白构象发生了改变。

Abstract:

Changes in the physicochemical properties of tilapia actomyosin under ultra-high pressure (100, 300, and 500 MPa for 15, 30, and 45 min) were investigated. The results revealed that an increasing pressure and a longer holding time could reduce the solubility of tilapia actomyosin, and the lowest solubility (89.17%) was observed with 500 MPa treatment for 45 min, indicating that ultra-high pressure could promote protein accumulation and denaturation. The Ca2+-ATPase activity of tilapia actomyosin was lost under ultra-high pressure, suggesting the degeneration of myosin. As the pressure and holding time increased, the surface hydrophobicity of actomyosin also increased, and the highest hydrophobicity was achieved with 300 MPa treatment for 45 min, indicating that ultra-high pressure allowed more hydrophobic groups to be exposed. The total sulfhydryl content of actomyosin was reduced with increasing pressure, and the lowest value was reached with the 500 MPa treatment for 30 min; the disulfide bond content increased, and the highest level was achieved with the 300 MPa treatment for 45 min, indicating that the sulfhydryl group of actomyosin underwent oxidation to form disulfide bonds. These changes in the physicochemical properties demonstrate that the conformation of tilapia actomyosin changes after ultra-high pressure processing.