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Impact of covalent interactions between caffeic acid and rice bran albumin on protein structure and function
Menglin Guo1, Ran Zhang1, Chenge Zhang1
1College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China.
Abstract:
To study the covalent interactions between plant proteins and phenolic acids that improve rice bran utilization, rice bran albumin (RBA) and caffeic acid (CA) were covalently complexed in an alkaline solution. The structure, interfacial properties, antioxidant activity, and in vitro digestion simulation of RBA-CA complexes were investigated. SDS-PAGE showed that albumin molecules were cross-linked. SEM, FTIR, and ANS fluorescence experiments demonstrated that CA modification changed the secondary conformation and surface hydrophobicity of the protein. RBA-CA complexes exhibited high antioxidant activity, with radical scavenging increasing by 48.52% (ABTS) and 33.08% (DPPH) upon CA modification. Additionally, the foamability and emulsification of RBA improved in medium- and low-concentration RBA-CA complexes. In vitro digestion results showed that adding CA increased RBA hydrolysis. The findings suggest that the covalent bonding of CA to RBA enhances the protein's functionality for food applications.
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