绿原酸改性黑芸豆蛋白抗氧化活性与乳化性能研究

Emulsifying Properties and Antioxidant Activities of Black Kidney Bean Protein Modified by Chlorogenic Acid

为解析黑芸豆分离蛋白(Black kidney bean protein isolate,BKPI)绿原酸(Chlorogenic acid,CA)复合体系中CA对BKPI功能性质的影响,研究了不同CA添加量(0.05、0.15、0.25 g/(100 mL))与BKPI相互作用后对BKPI结构及抗氧化特性和乳化特性的影响。采用动态光散射、荧光光谱和红外光谱等技术,研究流体动力学半径、内部结构特性及蛋白空间结构的变化。结果表明,随着CA添加量增加,复合物中多酚结合量与浊度增加,游离氨基含量减少,其溶液液滴粒径分布更加均匀。CA与BKPI的相互作用可以改变BKPI的空间结构,二级结构中α-螺旋与无规则卷曲的相对含量降低,β-转角的相对含量增加。随着CA添加量的提高,复合物乳化性及抗氧化性显著提高(P<0.05),当CA添加量为0.25 g/(100 mL)时,复合物的乳化性和抗氧化性最优。这表明在乳液食品体系中,CA-BKPI复合物可被用作有效的抗氧化剂和潜在的乳化剂。

In order to investigate the effects of covalent interaction of black kidney bean protein isolate(BKPI)and different concentrations of chlorogenic acid(CA)on the function of the protein,the effects of the covalent interaction of BKPI and different concentrations of CA on protein structure were studied.The relationship between structural change and the functional properties of the complexes was analyzed through dynamic light scattering,fluorescence spectroscopy and Fourier transform infrared(FTIR)spectroscopy.The results showed that the turbidity and the bonding content of CA in the complexes were increased,and its content of free amino group was decreased with the increase of CA concentration,the covalent interaction made the distribution of droplets in the solution more uniform.The secondary structure of BKPI was changed and the contents ofα-helix and unordered decreased,while the contents ofβ-sheet were increased,and resulting in its conformational change.The decrease in fluorescence intensity with the increase of CA concentration,indicating the unfolding of the protein structure.The addition of CA improved the antioxidant activities and emulsification properties of BKPI.When the concentration of CA was 0.25 g/(100 mL),the antioxidant activities(168.95μmol/g)and emulsifying properties of BKPI were the best.These results suggested that CA-BKPI complexes could be used as efficient antioxidants and potential emulsifiers in emulsion-food systems.