葡甘聚糖-乙基纤维素复合物制备及缓释特性研究

Kongjac glucomannan(KGM) was used as biological slow-release material. Its unique chemical structure and the molecules associating state has led to imperfection in the membranous, acid-proof alkaline, heat resistance, water resistance , therefore the mechanical properties of the films and fluid mechanics performance can't meet the extensive demands. This project is intended to prepare sustained release polysaccharide blend matrix by using the water-soluble KGM and water-insoluble ethylcellulose (EC) as primary materials to explore a new biological controlled release material approach. The blend process were monitored by using the static and dymamic laser light scattering instrumment and atomic force microscopy, after that the changes of molecular structure and aggregation state in solution on the stability, aggregation, and the phase separation of emulsion systems were analysed; Rheological properties of the blend matrix were analyzed by using the rheometer, and then the mechanism of polysaccharide films were explained; Use the differential calorimetry scanning, texture analyzer, water vapor adsorption meter, and the X-diffraction method, evaluating the comprehensive performance of complex films, and establishing the relation between polysaccharide complex and functional characteristics of rheological characteristics. The research can provide the theory evidence for the development of new polysaccharide and biological sustained release materials.

葡甘聚糖作为天然生物缓释膜基材，因其化学结构的特殊性及分子缔合状态导致其成膜的耐酸碱性、耐水性等存在缺陷，膜的机械性能、流体力学性能不能满足广泛需求。本项首次拟用水溶性的葡甘聚糖和水不溶性的乙基纤维素为基材，制备多糖复合物。针对乙基纤维素水不溶性特点以及二者混合后优势互补的可能性，探究新型生物缓释材料的途径。通过动静态激光光散射仪、激光共聚焦、原子力显微镜等监测葡甘聚糖和乙基纤维素复合的动态过程测定分子构象及分子聚集状态的改变，对形成的乳液体系的稳定、聚集和相分离过程的动力学进行研究；运用流变仪及纳米颗粒分布系统总结该复合物分散体系的流变学行为，探究多糖复合膜的成膜机理；运用示差量热扫描、质构仪、X-衍射仪等手段测定复合膜的结构和质构特征；运用水蒸气吸附仪、电位滴定仪测定复合膜的缓释特性，并建立多糖复合物流变特性与功能特性的相关性，为研究新的多糖基生物缓释材料提供理论依据。

葡甘聚糖作为天然生物缓释膜基材，因其化学结构的特殊性及分子缔合状态导致其成膜的耐酸碱性、耐水性等存在缺陷，膜的机械性能、流体力学性能不能满足广泛需求。本项首次用水溶性的葡甘聚糖（KGM）和水不溶性的乙基纤维素（EC）为基材，制备多糖复合物。针对EC水不溶性特点以及二者混合后优势互补的可能性，探究了构建新型生物缓释材料的途径。对所形成乳液体系的稳定、聚集和相分离过程进行了研究；运用流变仪及粒度分析仪系统地总结了该分散体系的流变学行为；通过FTIR、ITC、DSC、激光共聚焦、AFM等手段监测KGM和EC复合的动态过程，探究了多糖复合膜的成膜机理；运用水蒸气吸附仪、接触角测定了复合膜的亲疏水特性；探究了复合膜的包装、缓释特性，并建立多糖复合物结构特性与功能的相关性，为研究新的多糖基生物缓释材料提供理论依据。本研究得到以下结果：.1. KGM-EC混合乳液随着KGM/EC比率的变化呈现了两种相分离区和相溶区；成膜乳液在储藏过程中存在不稳定性相行为。当乳液中固形物含量一定时，KGM/EC比率越高，其在储藏稳定性变化程度越小。.2. KGM/EC成膜乳液样品呈现出剪切变稀的假塑性流动行为。乳液中固形物含量一定时，KGM/EC比率越高，活化能En越大，体系粘度下降随温度变化越显著。应力（应变）扫描发现乳液样品线性粘弹区在0.1～100Pa之间。小幅震荡频率以及温度扫描表明，KGM/EC成膜乳液中，KGM对材料的粘弹特性影响占主要作用。.3. KGM-EC复合膜成膜过程可以分为三个阶段：1）：EC油相均匀地分散在KGM水相中；2）：随着水和乙酸乙酯的蒸发KGM和EC分子间相互缠绕；3）：高聚物分子间相互扩散，最终形成致密均匀的薄膜。.4. KGM-EC复合膜具备水分活度敏感性，可拓展复合膜的应用。同时，KGM-EC复合膜可应用于低水分活度的食品或固体食品如蜂蜜、糖果、脱水蔬菜等，具有很好的应用前景。.5. 以不同比例混合KGM、EC、KGM-EC包膜尿素，获得了组合包膜尿素，尿素缓释，结果表明组合尿素释放率介于KGM-EC包膜尿素和EC包膜尿素之间。