本文研究了蔗糖癸酸酯对沙门氏菌的体外抗菌作用及其机理。采用肉汤稀释法测定了不同pH值下蔗糖癸酸酯对沙门氏菌的最小抑菌浓度（MIC）和最小杀菌浓度（MBC）。通过测定菌体渗漏物、SDS-聚丙烯酰胺凝胶电泳分析、扫描电镜观察、DNA结合试验等，初步研究了蔗糖癸酸酯对沙门氏菌的抗菌机理。结果表明：蔗糖癸酸酯在pH 7.0时对沙门氏菌的MIC为20 mM，在酸性条件下抗菌效果更为显著。蔗糖癸酸酯能够使菌体细胞内核酸、蛋白质和还原糖等外泄，影响细胞膜结构完整性和菌体正常形态；对菌体细胞蛋白（尤其是大分子量蛋白）的合成与积累有干扰作用；同时糖酯的亲水性头基可与DNA磷酸基团以氢键的方式结合，使DNA骨架收缩。因此，可将蔗糖癸酸酯作为兼具乳化和防腐作用的多功能食品添加剂，应用于动物源性食品的加工和储藏过程中。

In this study, the in vitro antibacterial activity of sucrose monocaprate against Salmonella Typhimurium was investigated, along with its underlying mechanism. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of sucrose monocaprate against S. Typhimurium were evaluated under different pH conditions using a broth macrodilution assay. The possible antibacterial mechanism against S. Typhimurium was preliminarily determined by evaluation of the released cellular constituents, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopic observations, as well as a DNA-binding assay. The results showed that the MIC of sucrose monocaprate at pH 7.0 against S. Typhimurium was 20 mM, and the antibacterial activity was more significant under acidic conditions. Treating S. Typhimurium with sucrose monocaprate led to the leakage of nucleic acids, proteins, and reducing sugars, as well as damage to the integrity of cell membranes, but with a normal cell morphology. Sucrose monocaprate interfered with the synthesis and accumulation of bacterial proteins (especially for high-molecular-weight proteins). Moreover, the hydrophilic head group of sucrose monocaprate could bind to the phosphate group of DNA by hydrogen bonding, which increased the contraction of the DNA backbone. Therefore, sucrose monocaprate can serve as a safe multifunctional food additive with both emulsifying and antibacterial activities, and shows potential to be applied in the processing and storage of animal-derived foods.

国家自然科学基金青年科学基金项目(31201324)；北京市教育委员会科技计划面上项目(KM201210011008)；北京市科技计划项目（Z15110500120000）