| Abstract: | The interactions between black soybean protein isolate (B‐SPI) and cyanidin 3‐O‐glucoside (C3G), anthocyanin extracted from black soybean coat was investigated under neutral conditions. The fluorescence spectra showed that C3G had fluorescence quenching effects on B‐SPI. Thermodynamic parameters showed that ? G < 0, which demonstrated that the binding was a spontaneous reaction. Since ΔH > 0 and ΔS > 0, the interactions between C3G and B‐SPI was mainly hydrophobic interactions. Fourier infrared spectroscopy results suggested that the contents of α‐helix and β‐sheet structure showed an increasing trend, whereas the β‐angle content displayed a decreasing trend. The degradation of C3G followed first‐order kinetics at 85 °C and 100 °C. After the interactions with B‐SPI, the degradation rate constant was decreased and the half‐life of C3G was prolonged from 70.25 ± 0.90 min to 175.64 ± 38.04 min at 85 °C, from 62.68 ± 1.1 min to 72.51 ± 2.5 min at 100 °C (p < 0.05). The results indicated that the interactions of B‐SPI and C3G improved the thermal stability of C3G under heating conditions. |
