In
the present study, soy protein isolate (SPI) was noncovalently
modified by (−)-epigallocatechin-3-gallate (EGCG), and its
foaming, emulsifying, and antioxidant properties were all significantly
increased. Fluorescence analysis revealed that the fluorescence quenching
of SPI by EGCG was static quenching. EGCG mainly changed the folding
state of SPI around Trp and Tyr residues, and the binding site was
closer to Trp. UV–vis spectra further proved that more hydrophobic
residues of SPI were exposed to a hydrophilic microenvironment. Circular
dichroism spectra indicated that the contents of ordered structures
were transforming into random coils with the reduce of α-helix,
β-sheet, and β-turns by 3.8%, 2.0%, and 1.2%, respectively.
Meanwhile, the binding stoichiometry of two molecules of EGCG per
one molecule of SPI was obtained from isothermal titration calorimetry,
and the interaction was a spontaneous endothermic process with a noncovalent
complex preferentially formed. According to thermodynamic parameters
and molecular docking model, hydrophobic force and hydrogen bonds
were considered to be the main interaction forces between SPI and
EGCG. Overall, after modification through the high affinity to EGCG,
the structure of SPI became looser and exposed more active groups,
thus resulting in an improvement of its foaming, emulsifying, and
antioxidant properties.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.