Investigation of the differences in the effect of (−)-epigallocatechin gallate and proanthocyanidins on the functionality and allergenicity of soybean protein isolate

Effects of Chlorogenic Acid on Lowering IgE-Binding Capacity of Soybean 7S: Comparison between Covalent and Noncovalent Interaction

“…UV absorption spectra is usually used to characterize the tertiary structure of proteins, and the UV absorption by proteins mainly originates from aromatic amino acids such as tryptophan and tyrosine . As shown in Figure B, it could be found that the 7S showed a UV absorption peak at 266 nm and the characteristic absorption peak of CHA in both noncovalent and covalent interaction samples appeared near 320 nm, which indicated that the 7S binded with CHA .…”

“…UV absorption spectra is usually used to characterize the tertiary structure of proteins, and the UV absorption by proteins mainly originates from aromatic amino acids such as tryptophan and tyrosine. 33 As shown in Figure 4B, it could be found that the 7S showed a UV absorption peak at 266 nm and the characteristic absorption peak of CHA in both noncovalent and covalent interaction samples appeared near 320 nm, which indicated that the 7S binded with CHA. 34 The noncovalent and covalent interaction samples showed concentration-dependent red-shift and the increase of UV absorption intensities compared with that of the 7S, which indicated that aromatic residues inside the 7S were exposed and the tertiary structure of the complexes unfold.…”

“…As shown in Figure B, it could be found that the 7S showed a UV absorption peak at 266 nm and the characteristic absorption peak of CHA in both noncovalent and covalent interaction samples appeared near 320 nm, which indicated that the 7S binded with CHA . The noncovalent and covalent interaction samples showed concentration-dependent red-shift and the increase of UV absorption intensities compared with that of the 7S, which indicated that aromatic residues inside the 7S were exposed and the tertiary structure of the complexes unfold . Most importantly, it could be speculated that the tertiary structure of the new complexes was related to the type of polyphenols interaction, because noncovalent interaction samples had more red-shift than covalent interaction samples in the same concentration.…”

“…34 The noncovalent and covalent interaction samples showed concentration-dependent red-shift and the increase of UV absorption intensities compared with that of the 7S, which indicated that aromatic residues inside the 7S were exposed and the tertiary structure of the complexes unfold. 33 Most importantly, it could be speculated that the tertiary structure of the new complexes was related to the type of polyphenols interaction, because noncovalent interaction samples had more red-shift than covalent interaction samples in the same concentration. Interestingly, the absorption intensity of the C-1 showed a slight decrease compared with that of the C-0.5, but the absorption peak of the C-1 still showed a red shift in wavelength compared with the C-0.5, while there was an absorbance intensity increase of the N-1 compared with the N-0.5.…”