Molecular Spectroscopy Analysis of Different pH-Cycle Self-Assembly Between Rice Glutelin and Egg White Protein Under Neutral Conditions

Self-assembly and molecular spectroscopy are widely used in protein research. However, studies underreported the interaction of rice glutelin (RG) and egg white protein (EWP) under pH-cycle treatments, which had differences between initial and final environment. Herein, the possible interaction mechanism of RG-EWP self-assembly behavior was demonstrated by spectroscopy or other characterization methods under different conditions and proportions. Fourier transform infrared, circular dichroism, intrinsic fluorescence, and UV absorption spectroscopic methods showed changes in the secondary and tertiary structures of RG or RG-EWP. Results also revealed the degree of protein folding and exposure status of aromatic amino acid residues. The nonignorable surface hydrophobic and electrostatic interactions were observed by ζ-potentials and surface hydrophobicity. The electrophoretic analysis showed increased 48 kDa subunits. The high solubility (over 92%) of RG-EWP was discovered as potential functionality at total ratio of 90% and 50% RG. This study improved the asymmetric pH-cycle theoretical mechanism and widened RG-EWP application.

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