Characterization and emulsification of BSA/theaflavins complexes

Abstract

Complex interactions occurring between proteins and polyphenols can impact the structural and functional properties of proteins, thereby enhancing their potential applications in food. We here used bovine serum albumin (BSA) as a prototypical protein for examining the structural and functional properties of the complex formed using theaflavins/BSA (BSA/TFs) in varying ratios. Additionally, the stability and rheological properties of the complex were analyzed as an emulsifier in high internal phase emulsions (HIPEs). According to the findings, the non-covalent bonding of TFs with BSA primarily involves hydrogen bonding, which changes BSA's secondary structure, including a reduction in α-helix and an increase in β-sheet. Additionally, BSA/TFs exhibited low interfacial tension, thereby forming a highly efficient adsorbent layer on the oil–water interface and improving the stability of the emulsion film. HIPEs stabilized using BSA/TFs as an emulsifier have good storage stability and rheological properties. The particle size of d(4, 3) after 30 days of storage was 19 μm. Regarding rheological properties, the elastic modulus was larger than the viscous modulus, which indicated the gel characteristics of the complex. The structural recovery degree was greater than 1, which demonstrated the anti-thixotropy and superior emulsification effect. This study provides a theoretical foundation and experimental direction regarding the implementation of protein–polyphenol complexes for augmenting food quality and functionality.