多糖可食用膜成膜中三维网状结构变化的研究

Polysaccharide-based films are used in food packaging because they are stable, safe and environment-friendly. The applicability of the films in food packaging is determined by its functional properties. The functional properties of polysaccharide-based films, including roughness, tensile strength and barrier properties, are significantly depended on the three-dimensional network formed by polysaccharide chains during the film-forming process. In this project, alginate film is taken as a case study, the effects of water evaporation and chain density on three-dimensional network structure are studied by time-resolved IR and low field singled-side NMR. Moreover, polysaccharide chains movement, conformation and the water-ionic-polysaccharide interactions, polysaccharide-polysaccharide interactions are analyzed by relaxation spectrum, 2D COS, NMR and 2D NMR. According to the macroscopic and microscopic information, a system to determine the change of three-dimensional network during the polysaccharide film formation will be established. These studies would provide some scientific basis for studying film-forming mechanism of edible films and their applications in food packaging.

多糖可食用膜是一类性能稳定、安全、环保的食品包装材料，其在食品中的应用主要取决它的包装性能，然而多糖可食用膜成膜过程中体系内三维网状结构的变化是决定其薄膜韧性、强度、气体的阻隔性能的重要因素。本项目旨在以海藻酸盐为多糖研究模型，使用时间分辨红外光谱、单边核磁共振成像仪技术，研究成膜过程中水分蒸发规律、大分子密度对网状结构的宏观影响；通过连续弛豫谱、二维红外光谱、核磁共振等技术，探索多糖大分子链段运动、构象以及水-离子-多糖、多糖-多糖相互作用等微观信息与网状结构特征变化的关系；拟建立系统的分析多糖可食用膜成膜过程中三维网状结构变化的方法。项目的顺利实施，为完善多糖类可食用膜成膜理论以及多糖可食用膜在食品包装中的应用提供一定的科学依据。

多糖可食用膜是一类性能稳定、安全、环保的食品包装材料，其在食品中的应用主要取决它的包装性能，然而多糖可食用膜成膜过程中体系内三维网状结构的变化是决定其薄膜韧性、强度、气体的阻隔性能的重要因素。本项目旨在以普鲁兰多糖、海藻酸钠为多糖研究对象，使用称重法研究了多糖可食用膜成膜动力学，包括成膜过程中传质传热、系数以及水分扩散系数等；运用傅立叶红外光谱结合二维相关性分析研究了水-多糖、多糖-多糖相互作用，以及大分子链段构象和链结构变化信息；使用流变仪研究了成膜过程中多糖大分子链段缠绕和弛豫谱信息；并利用低场核磁共振技术探索了多糖可食用膜成膜过程中水分子种类及其迁移规律，并结合diffusive and chemical exchange模型，阐述了成膜过程中多糖大分子三维网状结构尺度的变化；通过这些微观信息与多糖网状结构特征变化的关系，建立系统的分析多糖可食用膜成膜过程中三维网状结构变化的方法。这为完善多糖类可食用膜成膜理论以及多糖可食用膜在食品包装中的应用提供一定的科学依据。