摘要
采用不同浓度的2,2′⁃盐酸脒基丙烷[2,2′⁃azobis(2⁃amidinopropane),AAPH]有氧热分解产生的过氧自由基氧化花生球蛋白,研究AAPH氧化对花生球蛋白分子结构及聚集行为的影响。结果显示:随着AAPH浓度的增加,花生球蛋白表示浊度的吸光度由0.20±0.01增加至0.44±0.01,平均粒径从(153.94±3.31)nm增加到(196.80±3.06)nm,而游离巯基含量从(14.62±0.08)μmol/g下降到(7.77±0.25)μmol/g,Zeta电位绝对值从(24.17±0.06)mV下降到(15.93±0.05)mV。对荧光最大发射波长的研究表明,在AAPH浓度为0~1 mmol/L时,内源荧光最大荧光峰位红移,在AAPH浓度为5~15 mmol/L时,内源荧光最大荧光峰位蓝移。过氧自由基氧化导致花生球蛋白α⁃螺旋结构含量下降,β⁃折叠和无规则卷曲含量上升,呈现出α⁃螺旋向β⁃折叠和无规则卷曲转化的趋势。扫描电镜观察结果显示,花生球蛋白经过氧自由基氧化后,蛋白由聚集紧实逐渐变得发散,浓度从10 mmol/L升高到15 mmol/L时,花生球蛋白表面形态变疏松,孔隙显著增大。因此,AAPH适度氧化可以通过改变花生球蛋白的结构影响其聚集行为,特别是浓度为5~10 mmol/L时有利于花生球蛋白的聚集。
Arachin was oxidized by peroxide free radicals derived from aerobic thermal decomposition of 2,2′⁃azobis(2⁃amidinopropane)(AAPH)at different concentrations,and the effects of AAPH oxidation on the mo⁃lecular structure and aggregation behavior of arachin were investigated.The results showed that with the in⁃crease of AAPH concentration,the absorbance representing turbidity of arachin increased from 0.20±0.01 to 0.44±0.01,the average particle size increased from(153.94±3.31)nm to(196.80±3.06)nm,and the content of free sulfhydryl group decreased from(14.62±0.08)μmol/g to(7.77±0.25)μmol/g.The absolute value of Zeta potential decreased from(24.17±0.06)mV to(15.93±0.05)mV.The study on the maximum emission wave⁃length of fluorescence showed that when the AAPH concentration was 0-1 mmol/L,the maximum fluorescence peak of intrinsic fluorescence red⁃shifted,and when the AAPH concentration was 5-15 mmol/L,the maxi⁃mum fluorescence peak of intrinsic fluorescence blue⁃shifted.Peroxide free radical oxidation resulted in the de⁃crease ofα⁃helix content of arachin but an increase ofβ⁃sheet and random coil,showing a trend of transforma⁃tion fromα⁃helix toβ⁃sheet and random coil.The scanning electron microscopy results showed that after perox⁃ide free radical oxidation,arachin gradually dispersed from a tightly aggregated state.Especially,when the concentration increased from 10 mmol/L to 15 mmol/L,the surface morphology of arachin became loose,and the pores increased significantly.Therefore,moderate oxidation by AAPH can affect the aggregation behavior of arachin by changing its structure,particularly at the concentrations of 5-10 mmol/L,which is conducive to the aggregation of arachin.
作者
汪海燕
李玟君
李玉蝶
宋青云
庞子皓
肖一郎
汪超
李玮
WANG Haiyan;LI Wenjun;LI Yudie;SONG Qingyun;PANG Zihao;XIAO Yilang;WANG Chao;LI Wei(College of Biological Engineering and Food,Hubei University of Technology,Wuhan 430000,Hubei,China)
出处
《食品研究与开发》
CAS
2024年第7期49-54,65,共7页
Food Research and Development
基金
国家自然科学基金项目(31901643)。
关键词
花生球蛋白
过氧自由基氧化
二级结构
红外光谱
聚集行为
arachin
peroxide radical oxidation
secondary structure
infrared spectrum
aggregation behavior
