拉曼光谱分析荞麦多酚对米糠蛋白结构的影响

Effect of Buckwheat Polyphenols on the Structure of Rice Bran Proteins Analyzed by Raman Spectroscopy

利用拉曼光谱研究荞麦多酚对米糠蛋白的影响。结果表明:随着荞麦多酚添加量增加,米糠蛋白结构变化规律为α-螺旋结构含量逐渐降低,β-折叠结构含量呈现先增加后降低的变化趋势,β-转角结构含量呈先降低后增加的变化趋势,而无规则卷曲结构的含量逐渐增大;酪氨酸及色氨酸先趋于"暴露式"而后转为"包埋态",而荞麦多酚的添加使米糠蛋白二硫键由gauche-gauche-trans构型和trans-gauche-trans构型逐渐转变为gauche-gauche-gauche构型。因此,荞麦多酚与米糠蛋白的交互作用可部分破坏米糠蛋白分子间二硫键,降低米糠蛋白分子间作用,增强米糠蛋白结构的稳定性。

The effect of buckwheat polyphenols on the structure of rice bran proteins was studied by Raman spectroscopy in this research. Our results demonstrated that with increasing addition of buckwheat polyphenols, the secondary structures of rice bran proteins revealed a gradual decrease in α-helix content, an initial increase followed by a decrease in β-sheet content,an initial decrease and then an increase in β-turn content, and a gradual increase in random coil content. Furthermore,both tyrosine and tryptophan residues tended to be exposed at first and then transformed to a buried state. The addition of buckwheat polyphenols could lead to a configurational transformation of the disulfide bonds from gauche-gauche-trans and trans-gauche-trans to gauche-gauche-gauche. Therefore, the interaction between buckwheat polyphenols and rice bran proteins could partially damage the disulfide bonds in rice bran proteins and thereby enhance the structural stability of rice bran proteins.