Abstract: 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.

Key words: Raman spectroscopy, buckwheat polyphenols, rice bran proteins, structure