丙烯醛氧化对大黄鱼肌肉组织和肌原纤维蛋白结构性质的影响

采用不同浓度(0~10 mmol/L)的丙烯醛溶液对大黄鱼鱼肉进行体外模拟氧化,研究脂质次生氧化产物中的小分子醛类对大黄鱼肌肉组织和肌原纤维蛋白结构性质的影响。结果显示:丙烯醛处理会导致大黄鱼肌纤维缝隙变大,浓度达10 mmol/L时肌纤维发生断裂和小片化,达0.1 mmol/L以上可导致肌肉持水性的下降。当丙烯醛浓度大于0.1 mmol/L时,随着浓度增加,肌原纤维蛋白羰基含量、二聚酪氨酸含量、表面疏水性显著增高,总巯基含量显著减少;活性巯基对丙烯醛较为敏感,丙烯醛浓度为0.01 mmol/L时其含量比对照组减少了40.8%。SDS-PAGE电泳表明丙烯醛氧化能使蛋白质亚基发生交联,在200 ku上方区域形成聚集体。此外,氧化还能破坏肌原纤维蛋白的凝胶性质,使其凝胶强度、凝胶持水性、凝胶白度降低。上述结果表明,丙烯醛能够破坏大黄鱼肌肉组织结构,并能引起肌原纤维蛋白氧化,从而破坏其结构和功能性质。

Effects of Acrolein Oxidization on Muscle Structure and Myofibrillar Protein Structural Properties in Large Yellow Croaker (Pseudosciaena crocea)

In order to investigate the effects of small molecular aldehydes (among secondary lipid oxidation products) on the muscle structure and structural properties of myofibrillar proteins in large yellow croaker (Pseudosciaena crocea), the fish muscle was treated with different concentrations (0~10 mmol/L) of acrolein in an ex vivo oxidation experiment. The results showed that treatment with acrolein could lead to increased gaps between myofibers in large yellow croaker. Muscle fiber fracture and fragmentation occurred when the acrolein concentration reached 10 mmol/L, and the water-holding capacity of the fish muscle decreased when the acrolein concentration was greater than 0.1 mmol/L. The carbonyl content, bityrosine content, and surface hydrophobicity of the myofibrillar proteins increased significantly with an increase in the acrolein concentration above 0.1 mmol/L, whereas the contents of total sulfhydryl groups decreased significantly. Active sulfhydryl groups were sensitive to acrolein, and their contents decreased by 40.8% compared with the control at an acrolein concentration of 0.01 mmol/L. The SDS-PAGE results showed that acrolein oxidation could cause conjunction of some protein subunits, which formed aggregates in the area above 200 ku. In addition, the oxidation caused damage of the gel properties of the myofibrillar proteins, including decreases in the gel strength, water-holding capacity, and gel whiteness. All these results indicate that acrolein can damage the muscle structure of large yellow croaker and cause oxidation of the myofibrillar protein, thus damaging the structure and functional properties of the protein.