高温处理对牛肉蛋白质化学作用力及肌原纤维蛋白结构的影响

以牛背最长肌为研究对象，对其进行高温处理（110、115、121 ℃分别加热3、6、9、12、15 min），通过分析蛋白质化学键、傅里叶变换红外光谱、紫外光谱、内源荧光光谱以及蛋白质片段大小等结构信息变化，探讨高温处理对牛肉蛋白质化学作用力及肌原纤维蛋白结构的影响。结果表明，随着处理温度的升高和加热时间的延长，牛肉蛋白中离子键和氢键含量显著下降（P＜0.05），疏水相互作用和二硫键含量显著升高（P＜0.05）。肌原纤维蛋白二级结构发生重排，N—H和C—N伸缩振动以及N—H弯曲振动较为明显。高温处理促使芳香族氨基酸残基暴露于分子表面，并改变了肌原纤维蛋白质疏水区域的局部结构和蛋白质的三级结构。此外，在高温处理下肌原纤维蛋白发生了明显的降解聚集，并形成了大量小分子质量的蛋白片段。可见，高温处理能够显著改变牛肉蛋白质的化学作用力及肌原纤维蛋白的结构，本研究为高温处理下牛肉蛋白质变化机制的研究提供参考。

Effect of High Temperature Treatment on Chemical Forces of Beef Proteins and Structure of Myofibrillar Protein

Beef longissimus dorsi muscle was treated at different high temperatures (110, 115 and 121 ℃ for 3, 6, 9, 12 and 15 min, respectively). Structural changes in terms of protein chemical bonds, Fourier transform infrared, ultraviolet-visible and fluorescence spectra, and protein fragment size were analyzed in order to investigate the effect of high temperature treatment on chemical forces of beef proteins and the structure of myofibrillar protein. The results showed that contents of ionic bonds and hydrogen bonds in beef proteins significantly reduced (P < 0.05), whereas hydrophobic interaction and disulfide bond content increased significantly (P < 0.05) with increasing temperature and prolonged heating time. The secondary structure of myofibrillar protein was rearranged, and the stretching vibration of N?H and C?N and the bending vibration of N?H were clearly observed. After high temperature treatment, aromatic amino acid residues were exposed on the surface of the molecule, and the local structure of the myofibrillar protein hydrophobic region and the protein tertiary structure were changed. In addition, myofibrillar protein was degraded and aggregated significantly to form a large amount of small molecular mass protein fragments. Therefore, high temperature treatment can significantly change chemical forces of beef proteins and the structure of myofibrillar protein. This finding provides a basis for revealing the mechanisms of change in beef protein at high temperature.