Sucrose laurate and nisin synergistically inhibit Bacillus subtilis by multiple antibacterial targets and play promising application potential in bread preservation

Sucrose laurate, a commonly used emulsifier, was investigated to explore its preservative effect combined with nisin using Bacillus subtilis as indicator. The results suggested that sucrose laurate and nisin exhibited synergistic antibacterial effect with the fractional inhibitory concentration index of 0.5. Moreover, antibacterial mechanism assays revealed that sucrose laurate and nisin compromised the cell wall integrity by retarding peptidoglycan synthesis, dissipated membrane potential, damaged membrane permeability by inactivating the Na⁺K⁺-ATPase via hydrogen bonding interaction to trigger K⁺ leakage, and destroyed cell membrane integrity concurrently with the leakage of protein and nucleic acid; SEM observation revealed their remarkable ability to disrupt cell ultrastructure and induce morphological shrinkage; Gel retardation results demonstrated the alternation in protein expression patterns. Furthermore, the promising effect of sucrose laurate and nisin was evidenced in bread exhibiting extended shelf life. Conclusively, this research could provide scientific basis for expanding the application of sucrose laurate in food industry.