羟自由基氧化对花生球蛋白结构和功能性质的影响

为深入研究自由基氧化对花生球蛋白的影响,建立由铁/过氧化氢/抗坏血酸组成的羟自由基氧化体系,通过控制过氧化氢浓度对花生球蛋白进行不同程度的氧化处理,考察羟自由基氧化对花生球蛋白结构和性质的影响。研究表明,随着过氧化氢浓度的增大,花生球蛋白的羰基含量、浊度、起泡稳定性呈上升的趋势;游离巯基、总巯基、溶解度和表面疏水性呈现明显下降的趋势;乳化性、乳化稳定性和起泡性呈先上升后下降的趋势;紫外扫描图谱表明,氧化导致花生球蛋白的紫外吸收峰强度明显减弱,最大波长发生轻微蓝移;差示扫描量热法结果显示,羟自由基修饰后的花生球蛋白的放热峰依次为74、72、70、75、70、72、73℃,与对照组(72℃)相比无明显变化;圆二色谱分析表明,随着过氧化氢浓度的增加,花生球蛋白的二级结构发生改变,其α-螺旋结构明显减少,无规则卷曲结构明显增加。结果表明,羟自由基氧化对花生球蛋白的性质和结构有较大影响,可通过适度氧化对花生球蛋白结构和功能性质进行调控,获得具较好乳化性和起泡性的花生球蛋白。

Effects of hydroxyl radical oxidation on the structure and functional property of arachin

This study aimed to in-depth explore the effects of free radical-induced oxidation on arachin.A hydroxyl radical oxidation system composed of iron/hydrogen peroxide/ascorbic acid was established,and arachin was oxidized to a variable extent by varying the concentration of hydrogen peroxide,then the influence of hydroxyl radical-induced oxidation on the structure and property of arachin was investigated.The results showed that the carbonyl content,turbidity,and foaming stability of arachin increased with the increasing of hydrogen peroxide concentration.Meanwhile,the free sulfhydryl group,total sulfhydryl group,solubility,and surface hydrophobicity significantly decreased,while the emulsification,emulsification stability,and foaming property increased firstly and then decreased.Moreover,the UV scanning spectra showed that the absorption peak intensity of arachin decreased obviously after oxidation,and the maximum wavelength showed a slight blue shift.Differential scanning calorimetry showed that the exothermic peaks of arachin modified by hydroxyl radical were 74,72,70,75,70,72,73℃,respectively,and there was no significant change compared with the control group(72℃).Furthermore,the circular dichroism analysis showed that the secondary structure of arachin was changed with the increase of hydrogen peroxide concentration such as theα-helix structure was decreased,and the irregular curled structure was increased.The result showed that the hydroxyl radical-induced oxidation had a great influence on the structure and property of arachin.The structure and functional properties of arachin can be regulated by moderate oxidation to obtain arachin with good emulsification and foaming property.