负载NO供体的明胶微球的分子组装、缓释行为及抑菌机制研究

亚硝酸盐对肉类工业的贡献是巨大的，但其抑菌机制仍不明确。最近的医学研究表明含硝化合物分解产生的NO能抑制多种细菌生长及其生物膜形成。因此，探索亚硝酸盐与NO抑菌的关联性及开发新型NO供体是降低亚硝酸盐使用量的重要途径。本项目基于生物大分子组装与酶法交联原理，利用TGase与漆酶分别交联A型与B型明胶，并结合冷诱导成胶方法，制备负载亚硝酸钠及其他NO供体的明胶微球，并对其微观结构、理化特性及NO包埋率等进行分析，明确材料属性与NO负载行为的关联机制；探索微球在不同条件下NO释放动力学，建立NO控释模型，结合NO释放过程中微球结构及理化特性变化，研究微球结构与NO缓释行为的关联性，揭示微球释放NO机制；评估包埋不同NO供体的微球对香肠的抑菌效果，从细胞与分子层面阐明NO对香肠表面优势菌群的抑菌机制，从而为在肉制品中安全使用亚硝酸盐及其他NO供体，延长肉制品保质期提供理论基础。

The contribution of nitrite to meat industry is huge, but its specific antibacterial mechanism is still unclear. However, several recent medical studies have shown that NO produced by the decomposition of nitrate-containing compounds could inhibit the growth of a variety of bacteria and their biofilms formation. Therefore, it is important to explore the relationship between nitrite and anti-bacteria of NO and to develop new NO donors in order to reduce the use of nitrite in meat products. In this study, type A and type B gelatin microspheres loaded with sodium nitrite and other NO donors will be prepared based on the principle of biomacromolecule assembly and enzymatic crosslinking, combining with the cold-induced gelling method, where TGase and laccase will be used to cross-link type A and type B gelatin, respectively; then the structure, physical and chemical properties, and NO embedding rate of microspheres will be characterized, and the correlation mechanism between the properties of materials and the loading behavior of NO will be clarified. Moreover, the NO release kinetics of microspheres at different conditions will be explored and a controlled releasing model of NO will be established accordingly; likewise, the NO releasing mechanism of microspheres can be revealed by combining the structure and physicochemical properties changes of microspheres during NO releasing and the relationship between microspheres structure and sustained-releasing behavior. Finally, the antibacterial effect of microspheres loaded with sodium nitrite and other NO donors on sausage will be evaluated and compared; furthermore, the dominant spoilage bacteria on the surface of sausage will be taken as the model bacteria to clarify the antibacterial mechanism of NO from cellular and molecular levels, respectively. The results of this study can provide some basis for the safe use of nitrite and other NO donors in meat products and extend the shelf life of meat products.