鱼皮明胶及与果胶复合凝胶水化形成与降解机理

Gelatin is an important raw material for food and some related industries. As a new source of gelatin, fish skin has a potential huge market demand. However, physical properties such as texture and viscosity have limited the application of gelatin from fish skin. In this study, based on the changes of nanostructure and physicochemical properties, physicochemical process of gelatin will be elaborated at a molecular level by the analyses of hydration mechanism. Atomic force microscope (AFM) will be applied and corresponding techniques will be developed to characterize and manipulate the nanostructure of gelatin macromolecules. Appropriate sample preparation, imaging parameters and molecular manipulation procedures will be developed for nanostructure images of high concentration of gelatin. Impact of freezing temperatures, storage time and additives especially pectin on the gelatin crosslink and degradation will be predicted through characteristic parameters of singale molecule and aggregates, which can be derived from AFM images. Texture properties and viscosity of each type of gelatin gel will be obtained. Meanwhile, protein subunits and amino acid composition will be assayed by gel electrophoresis and high performance liquid chromatography (HPLC), respectively. Analyses of relationship between nanostructure and physicochemical properties could elucidate fundamental mechanism of gel forming and degradation. The results can be applied for elucidating the fundamental reason causing different physicochemical properties of gelatins, which could be applied for improving texture measurements and providing guidance for modification and application of fish skin gelatin.

明胶是食品和相关工业的重要原料。鱼皮作为新的明胶原料有着巨大的市场需求，但由于质地和粘度等物理特性限制了鱼皮明胶的应用。本研究从纳米结构与明胶理化特性的变化出发，通过研究鱼皮明胶纳米结构形成的水化机理，从分子角度阐述明胶理化特性的变化过程。利用原子力显微镜技术表征和操纵明胶的纳米大分子结构，开发合适的样品制备、成像参数以及分子操纵技术得到高浓度明胶的纳米结构图像。通过鱼皮明胶原子力显微镜图像中单分子及聚集体特征定量参数推测冷藏温度、贮藏时间及添加物特别是添加果胶对明胶的交联和降解的影响，测定各组分明胶和凝胶的质构特性和粘度，利用电泳和液相色谱分析蛋白亚基及氨基酸组成，运用相关性分析明胶和凝胶纳米结构与宏观理化特性的关系，得到明胶凝胶形成和降解机理，研究结果可用于揭示明胶理化特性不同的结构原因，改进质构测试方法，为鱼皮明胶改性和应用提供理论指导。

明胶是食品和相关工业的重要原料。鱼皮作为新的明胶原料有着巨大的市场需求，但由于质地和粘度等物理特性限制了鱼皮明胶的应用。本项目通过研究食品其它组分和添加成分对明胶结构和理化特性的影响，从分子角度详细阐述了明胶理化特性的变化过程；并开发了明胶分子的原子力显微镜表征和操纵技术；在此基础上，通过研究测定了不同冷藏温度下明胶的特性，推测了明胶大分子交联方式及降解模式；同时，通过宏观与微观变化的关联研究，得到了反映明胶质地变化的物性仪测定方法，分析揭示了明胶理化特性不同的结构原因，为鱼皮明胶的改性和应用提供理论指导。