自由基氧化对猪肌球蛋白-醛类化合物吸附特性的影响

采用FeCl3/抗坏血酸/H2O2羟自由基氧化体系模拟猪肌球蛋白氧化，研究不同H2O2浓度对肌球蛋白巯基总量、活性巯基、二级结构和表面疏水性的影响及与4?种典型醛类风味物质间的相互作用。结果表明：H2O2浓度对蛋白质构象有显著影响，随着H2O2浓度逐渐增加，活性巯基含量显著下降（P＜0.05），表面疏水性显著增加（P＜0.05）。当H2O2浓度在0～5?mmol/L之间时，巯基总量、α-螺旋相对含量显著下降（P＜0.05），蛋白质吸附能力显著增强（P＜0.05）；当H2O2浓度在5～10?mmol/L之间时，α-螺旋相对含量显著上升（P＜0.05），蛋白质吸附能力显著减弱（P＜0.05）；当H2O2浓度在10～20?mmol/L之间时，蛋白质吸附能力显著增强（P＜0.05）。肌球蛋白与醛类化合物间的作用力主要为氢键和疏水相互作用，氢键和（或）疏水相互作用越强，蛋白质对醛类化合物吸附能力越强。

Binding Capacity between Porcine Myosin and Aldehyde Compounds as Affected by Hydroxyl Radical

The effect of oxidation on protein conformation and binding capacity of porcine myosin were investigated in vitro using a FeCl3/Asc/H2O2 hydroxyl radical oxidation system. The contents of total and reactive sulfhydryl groups, secondary structure and surface hydrophobicity were detected as a function of H2O2 concentration, and the interactions between porcine myosin and four typical aldehyde compounds responsible for the flavor were investigated. It was demonstrated that the protein conformation was significantly affected by H2O2 concentration. The content of reactive sulfhydryl groups was significantly decreased while surface hydrophobicity was significantly increased with the increase of H2O2 concentration (P < 0.05). The contents of total sulfhydryl groups and α-helix were significantly decreased (P < 0.05) while the binding capacity between myosin and aldehyde compounds was significantly increased in the H2O2 concentration range from 0 to 5 mmol/L (P < 0.05). The α-helix content was significantly increased while the binding capacity of myosin was significantly decreased with increasing H2O2 concentration to 10 mmol/L (P < 0.05). The binding capacity of myosin was significantly increased again with further increasing H2O2 concentration to 20 mmol/L (P < 0.05). The main binding forces between aldehyde compounds and myosin were hydrogen bond and hydrophobic interaction. Stronger hydrogen bond and/or hydrophobic interaction led to a higher binding capacity of myosin to aldehyde compounds.