弹簧糊精聚集体附载气体自组装机理及释放规律研究

Microencapsulation gas-solid adsorption system is reversible, and shows slow release characteristics with potential applications in areas of food, agriculture and medicine. Ethylene is encapsulated in the flexible single helix amylose in the form of spring dextrin aggregates, which is of great practical significance to provide safe and efficient use of gas, and develop new methods of fresh-keeping for fruit and vegetable. Different degrees of polymerization and aggregation state structure of spring dextrin will be designed and prepared using starch as raw material. The gases will be entrapped into spring dextrin in water or solid system. The effects of temperature and pressure conditions on the complexation rule will be investigated. The complexation pattern between spring dextrin molecules and gases, and how the complexes aggregate into particles will be studied. The crystalline structure, granule size, micro-porous structure and thermal properties will be analyzed in order to uncover the self-assembly mechanism. The release property and rules of the complex, and the relationship between structure (molecular and aggregation state structures) and function (encapsulation rate and release rate) will be investigated for application in the fruit storage. Results will provide theoretical guide for developing new adsorption material for gas encapsulation.

气-固微胶囊吸附体系具有可逆性和缓慢释放的特点，在食品、农业和医药等领域都具有潜在的应用。将乙烯等气体附载于直链淀粉单螺旋结构聚集而成的弹簧糊精聚集体中，达到缓释效果，对安全、高效使用气体，开发新型果蔬气调保鲜方法等方面都具有重要的现实意义。本项目以淀粉为原料，设计并创制具有不同聚合度分布和聚集态结构的弹簧糊精聚集体，分别在水介质体系或以聚集体颗粒形式附载气体，研究不同温度、压力等物理参数下弹簧糊精与乙烯等气体的络合规律，探讨络合物中弹簧糊精单螺旋分子与气体的结合方式，单分子络合物聚集体颗粒的结晶结构、颗粒粒径、微孔结构和热力学性质，揭示弹簧糊精捕获非极性气体分子的自组装机制；研究络合物中单螺旋数量和结晶结构对包埋率的影响，气体在不同条件下的释放规律及在果蔬保鲜中的应用，构建络合物的一级结构、聚集态结构与气体包埋率的构效关系，为开发高效吸附兼具缓释效果的气体吸附捕捉新材料提供理论指导。

采用淀粉及其降解产物糊精分别构建不同空腔结构的V型结晶淀粉、α-环糊精金属有机框架（MOFs）和线性糊精乙烯负载体，考察不同载体结构与乙烯负载率的关系，研究不同载体的乙烯吸附机制与构效关系，明晰络合物中气体在不同环境中的释放规律，为丰富气体自组装理论提供理论指导。结果发现，不同种类（直链淀粉含量不同）V型结晶淀粉的乙烯负载性能存在显著差异，负载量在8.0~31.8%，且与直链淀粉含量成正相关。韧化处理显著提高了V型结晶淀粉的乙烯负载量(18.1~49.6%)，且淀粉的无定型结构在韧化过程中重排形成V型结晶。为进一步探究V型单螺旋结构对乙烯的负载及缓释规律，采用酶解和分级醇沉的方法制备不同聚合度的线性糊精，发现乙烯负载及缓释性能与V型单螺旋结构显著相关，V型结构越多 (4.8-38.1%)，其负载及缓释性能越好。同时，采用甲醇扩散法制备α-CD-MOF-K和α-CD-MOF-Na，考察其对乙烯的负载性能，发现乙烯负载量分别为47.3%和52.9%，且α-CD-MOF-K呈现出较好的释放性能，在25°C储存30天后，仅释放50.1%。该研究为构建具有高效附载气体的载体提供理论基础，同时极大地丰富和发展了天然高分子与气体自组装理论，在果蔬保鲜领域具有潜在的应用前景。