Raman Spectroscopy investigate structural change of rice bran protein induced by three oxidants

ABSTRACT The effects of lipid peroxidation on rice bran protein (RBP) structure was examined through Raman Spectroscopy. 2,2’-azobis (2-amidinopropane) dihydrochloride (AAPH), acrolein, and malondialdehyde (MDA) are chosen for lipid peroxidation. Incubation of RBP with the increasing concentration of three oxidants resulted in a gradual generation of protein carbonyl derivatives. It can be deduced from the Raman spectra that a low concentration of AAPH and acrolein both decreased the percentage of α-helix and β-sheet, which increased with MDA concentration. The Raman intensities of tryptophan residues of oxidized RBP by AAPH and acrolein, both initially increased and then decreased with oxidation concentration. After MDA treatment, the Raman intensities corresponding to Trp residues and Tyr doublet ratio of RBP were increased and then decreased, and decreased and then increased with oxidation concentration, respectively. The structural change induced by RBP oxidation with the Raman Spectroscopy can aid in refining the function of RBP characteristics and control the adjustment of the storage condition.