State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, China.
State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, China; National R&D Center of Freshwater Fish Processing, Jiangxi Normal University, Nanchang 330022, China; Engineering Research Center of Freshwater Fish High-Value Utilization of Jiangxi Province, Jiangxi Normal University, Nanchang 330022, China.
Food Res Int. 2023 May;167:112652. doi: 10.1016/j.foodres.2023.112652. Epub 2023 Mar 10.
The aim of this study was to investigate the phase behavior and structural properties of fish gelatin complex coacervation with carboxylated chitosan as a function of pH by varying the amount of carboxylated chitosan added (0-0.25%, w/v) while keeping the fish gelatin concentration constant at 0.667% (w/v). Zeta potential indicated that electrostatic interaction drove the complex coalescence of fish gelatin and carboxylated chitosan to form soluble or insoluble complexes. The turbidity of the fish gelatin-carboxylated chitosan complex system was greatest at a carboxylated chitosan concentration of 0.2%. UV and fluorescence spectroscopy indicated that the carboxylated chitosan changed the tertiary conformation of fish gelatin. Circular dichroism showed that complexation of fish gelatin with carboxylated chitosan resulted in a shift from the α-helix to the β-sheet structure of fish gelatin. In particular, at pH 5, the fish gelatin complexed with carboxylated chitosan had a disordered structure. X-ray diffraction and scanning electron microscopy of the composite coacervates both investigated that electrostatic interaction between the two replaced molecular interaction within the carboxylated chitosan to form a new lamellar porous structure. These findings may in future enable the use of fish gelatin-carboxylated chitosan complex systems in the design of new food matrices.
本研究旨在通过改变添加的羧甲基壳聚糖的量（0-0.25%，w/v），同时保持鱼明胶浓度不变（0.667%，w/v），研究鱼明胶与羧甲基壳聚糖的复凝聚相行为和结构特性与 pH 的关系。Zeta 电位表明静电相互作用驱动了鱼明胶和羧甲基壳聚糖的复合凝聚，形成可溶或不可溶的复合物。在羧甲基壳聚糖浓度为 0.2%时，鱼明胶-羧甲基壳聚糖复合体系的浊度最大。紫外和荧光光谱表明羧甲基壳聚糖改变了鱼明胶的三级构象。圆二色性表明鱼明胶与羧甲基壳聚糖的复合导致鱼明胶从α-螺旋结构向β-折叠结构转变。特别是在 pH5 时，与羧甲基壳聚糖复合的鱼明胶具有无序结构。复合凝聚物的 X 射线衍射和扫描电子显微镜研究表明，两种物质之间的静电相互作用取代了羧甲基壳聚糖内的分子相互作用，形成了一种新的层状多孔结构。这些发现可能使未来能够在设计新型食品基质中使用鱼明胶-羧甲基壳聚糖复合体系。
