Study on the Protective Effect and Mechanism of Flos sophorae immaturus Extract and Its Main Active Ingredient Rutin on Meat Color

Meat color directly affects consumers’ purchase intention of meat, which is mainly affected by myoglobin (Mb). The extract of Flos sophorae immaturus (FSI) and its main active ingredient rutin (52% of the FSI extract) show potential in preserving beef color. In this study, their protective effects and mechanisms were investigated by spectral analysis, molecular docking, and molecular dynamics simulation. Results indicated that rutin exhibited superior color protection: Beef treated with rutin maintained higher redness and brightness during 7 days of 4 °C storage, with MetMb% maintained at 45–47% and stable pH values around 5.5. Mechanistically, rutin spontaneously formed stable noncovalent complexes with Mb mainly through van der Waals forces and hydrogen bonds, inducing Mb aggregation, altering its secondary structure, reducing surface hydrophobicity and solubility, and enhancing thermal stability (denaturation temperature increased from 77.80 to 133.25 °C). These findings provide a theoretical foundation for developing novel natural meat color protectants.