Physical and antibacterial properties of soybean isolate protein nanoparticles co-encapsulated with benzyl isothiocyanate and resveratrol

The aim of this study was to investigate the synergistic effect of benzyl isothiocyanate (BITC) and resveratrol (RES) on Staphylococcus aureus ( S. aureus ), the controlled release of the corresponding nanoparticles, and their application in beef preservation. The synergistic antibacterial effect of BITC and RES on S. aureus was determined using a checkerboard assay and time-to-kill kinetic analysis. The particle size, polydispersity index, zeta potential, Fourier transform infrared spectroscopy and X-ray diffraction results showed that BITC and RES were successfully encapsulated by the soybean protein isolate (SPI). The results of the first-order kinetic model indicated that the regression coefficient (R 2 ) values were 0.92–0.98. In addition, the molecular docking results showed that the docking scores of BITC, RES and BITC-RES with SPI ranged from −6.3 to −9.7 kcal/mol, indicating the stability of these nanoparticles. At 36 h, BITC-RES inhibited S. aureus 2.7–3.6 times more than the treatment group alone. SPI-BITC-RES inhibited S. aureus 2.5 times more than did BITC-RES at 48 h. Compared to those in the control group, the numbers of S. aureus in the SPI-BITC and SPI-RES groups decreased by 0.78 CFU/mL and 0.77 CFU/mL, respectively, while the number of S. aureus in the SPI-BITC-RES group decreased by 1.54 CFU/mL. The Gompertz model was used to predict the growth of S. aureus in beef treated with BITC, RES, BITC-RES and the corresponding nanoparticles, with R 2 values greater than 0.90. Therefore, these results suggested that BITC-RES nanoparticles are expected to be useful for food preservation.