Changes in the structural, aggregation behavior and gel properties of pork myofibrillar protein induced by theaflavins

This study explores the effect of different theaflavins (TFs) concentrations (0, 100, 300, 600 and 900 mg/L) on the structure, aggregation behavior and gelation properties of pork myofibrillar protein (MP). The protein structure and aggregation behavior were characterized by free sulfhydryl groups, surface hydrophobicity, fluorescence emission spectra, particle size and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDSPAGE). The gel properties of samples were characterized by gel strength, cooking loss, microstructure and gel supernatant SDS-PAGE. The results showed a significant decrease in free thiol content with increasing TFs concentration, suggesting thiol-quinone covalent interaction between TFs and thiol group of MP. Intrinsic fluorescence spectroscopy confirmed a static quenching between TFs and MP. And TFs reduced the particle size of MP suspension and caused no protein aggregation bond in SDS-PAGE. For gel properties, TFs caused a decrease of gel strength from 96.77 g to 21.91 g and an increase in cooking loss from 40.34 % to 71.15 %. The bond of protein aggregates in gel supernatants SDS-PAGE revealed that some protein aggregates formed by disulfide bonding were not involve in gel formation with TFs addition. In conclusion, TFs cause thiol loss of MP and impaired MP gelling ability by interfering with disulfide bond formation during gelation.