蛋白质氧化对核桃蛋白界面性质的影响

Effect of Protein Oxidation on Interfacial Properties of Walnut Protein

采用不同浓度(0~10 mmol/L)的丙二醛替代脂质过氧化反应中产生的活性醛氧化核桃蛋白,研究蛋白质氧化对核桃蛋白界面性质的影响。试验结果表明:随着丙二醛浓度的增加,核桃蛋白发生显著氧化,羰基含量从3.12 nmol/mg增至20.61 nmol/mg。随着核桃蛋白氧化程度的增加,核桃蛋白粒径分布发生偏移,蛋白质相对分子质量先减小后增加,表面张力呈先下降后上升的趋势,Zeta电位绝对值、表面疏水性、起泡性和泡沫稳定性呈先增加后减小的趋势。当蛋白质氧化体系中的丙二醛浓度为0.1 mmol/L时,表面张力达到最小值,即55.64 mN/m;核桃蛋白的Zeta电位绝对值、表面疏水性、起泡性和起泡稳定性达到最大值,分别为10.38 mV,476,21.43%,17.80%。研究结果表明:丙二醛氧化诱导使得核桃蛋白的分子结构和界面性质发生改变,较低程度的氧化有利于改善核桃蛋白的界面性质。

The objective of this research was to study the effect of oxidization of malondialdehyde which was selected as a representative of reactive aldehydes produced in the process of polyunsaturated fatty acids lipid peroxidation catalyzed by lipoxygenase on the surface properties of walnut protein.Increasing extent of oxidation resulted in gradual carbonyl group generation and carbonyl content of walnut protein were increased from 3.12 nmol/mg to 20.61 nmol/mg.With the degree of oxidization was increased,the particle size of walnut protein was deviated,the relative molecular weight of protein first decreases and then increases and surface tension of walnut protein showed a trend of decrease first and then increase,as well as,the results of absolute value of Zeta potential,surface hydrophobicity,foaming capacity and foaming stability showed the trend of increase first and then decrease.When the concentration of malondialdehyde was to 0.1 mmol/L,the value surface tension of walnut protein reached the minimum,which was 55.64 mN/m,respectively;and the absolute value of Zeta potential,surface hydrophobicity,foaming capacity and foaming stability reached the maximum value,which were 10.38 mV,476,21.43%and 17.80%,respectively.Experimental results showed that the molecular structure and interface properties of walnut protein were changed with the oxidation of protein by malondialdehyde,and the interface properties of walnut protein could been improve at low degree of oxidation.