长效缓释香精分子设计与香气控释机制研究

The sustained release flavor has become the key point of traditional light industry products (account for 1/3 of GDP) upgrading and also has a significant influence on our national economy and people's living condition in China. Considering the problems in aroma release process which happened in the ink, paper and cotton fabric and the action mechanism between the flavor and the substrate were not clear，the purpose of this project is to design the exactly matching flavor molecule by using molecular modification, self-assembly and host-guest inclusion complexation. Moreover, this study put more attention on how to use polyethylene glycol and methoxypolyethylene glycols to modify the fragrance molecule and how to use maltodextrin, starch octenylsuccinate and hydroxypropyl-β-cyclodextrinto embed the flavor. Similarly, on the basis of studying the effects of different process parameters on aroma release and the calculation method of fuzzy mathematics, molecular simulation and quantum chemistry, we simulate the formation of the sustained release flavor and aroma release. Furthermore, we conduct a research on the mode of action between flavor molecule and wall material which reveal the mechanism of aroma control of sustained release flavor. The effects of different parameters on aroma release were investigated by regulating and controlling particle size, morphology and surface morphology of various systems. Nothing reported by any other domestic and foreign essays concerning this study but the relative articles and research work conducted by our research group. This project provides theoretical guidance for the new method of preparation and application for the flavor and promotes the overall level of our country's flavor and fragrance industry.

长效缓释香精已成为制约我国传统轻工类产品（占GDP总量1/3）升级换代的关键，对国民经济与人民生活影响重大。针对目前香精在油墨、纸张、棉织品中香气释放过程不清楚，香精与基材间的作用机制不明确等科学问题，本项目旨在根据基材结构特性，设计精确匹配的香精分子，利用分子修饰、自组装和包结络合方法，重点研究以聚乙二醇、聚乙二醇单甲醚为模型物进行香料分子修饰，以麦芽糊精、辛烯基琥珀酸淀粉酯和羟丙基-β-环糊精为壁材进行香精包覆，通过调控不同体系的粒径、形态、表面性质等特性参数，系统考察不同过程参数对香气释放行为的影响；并根据模糊数学、分子模拟和量子化学计算方法，对缓释香精形成与香气释放过程进行模拟，探究香精分子与基材之间的作用方式，揭示长效缓释香精的香气控释机制。相关研究除本课题组发表的文章和预研工作外，尚未见国内外文献报道。本项目研究为新型香精制备及其应用提供理论指导，促进我国香精行业整体水平提升。

本项目通过长效缓释香精结构设计、反应合成、实验表征等手段，并借助于拟合模型，系统研究了不同长效缓释香精体系反应参数等对粒径大小及分布的影响、结构设计对缓控释机制、加香体系缓释性能的影响。对基于聚乙二醇潜香分子合成与缓释性能研究表明：单取代物收率高于双取代物，聚乙二醇链长对酯化反应有位阻效应。引入聚乙二醇修饰单元后的潜香分子相比桂酸单体实现了约50~80倍提升。潜香分子的释放曲线均符合一级动力学方程并遵循Arrhenius方程模型。在pH值为2.0、5.5、10.0和12.0的缓冲溶液中的桂酸释放速率ki依次为8.00×10-5、1.50×10-6、2.18×10-4和5.72×10-2 min-1；在25、40与60℃下，桂酸释放速率ki依次为3.33×10-2、5.72×10-2和9.78×10-2 min-1；三种潜香分子释放速率ki依次为5.72×10-2、6.10×10-2和4.82×10-2 min-1。潜香分子负载的棉织物在存储过程中香气挥发损失很少，120天时桂酸释放率为45%，而参比物的仅为1%，所设计合成的潜香分子可以很好地实现香气的缓控释效果。对基于麦芽糊精和辛烯基琥珀酸淀粉酯的缓释玫瑰香精体系研究表明：缓释香精平均粒径为2.22±0.03 μm，载香量45.27± 0.56%。Avrami’s 方程对香气物质保留率和释放时间拟合发现，酯类物质释放最快，醇类其次，酚类物质释放最慢。超分子体系在OSA淀粉比例低、壁材添加量小、体系为酸性或中性、体系盐浓度低时可自组装形成囊泡，反之则形成胶束。对基于β-环糊精分子包络苹果香精体系的研究表明：最佳参数条件下缓释香精包封效率和装载量分别为79.8%和6.78%，粒径在2.6-7.2 µm之间（平均值3.6 µm）。红外与DSC均显示苹果香精受到分子间作用力形成了分子包络物。60天后，苹果香精/β-环糊精包合物中香精随时间的保留率在4、25、50℃时分别为96％，66.8％和34.4％。Avrami方程回归分析表明：4℃时释放机理参数n为0.65921，释放过程介于扩散限制动力学和一级释放动力学之间。25℃和50℃释放机理参数n分别为1.32747和1.19095，其值接近1，符合一级释放动力学。与普通香精相比，缓释香精加香的芳香棉织物具有更好的缓释性能，香味保持能力更持久。