香料微胶囊微结构对香料稳定性及安全性的影响机制与评价

Microcapsulation is an important technique to protect flavors and control the releasing of flavors.However,current reports on protection of flavors through microcapsulationare still qualitative research,and there are no reports about the effects of microstuctures (diameter, micropores, wall thinckness, surface chemistry, etc.) on the stability and safety of flavors. Therefore, in this project, flavor microcapsules will be prepared through several widely used methods,using pure flavor chemicals with different chemical structures and pure essentical oils as the core materials and polysacchrides with different hydrophilicity/hydrophobicity as the wall materials. The microstructures of the microcapsules and flavor components variation will be measured. The oxygen and water mass transfer effeciency will be measured and computational modeled. According to above results, the effection mechanism of flavor microcapsules micorstrutures and the relevant evaluation on the stability and safety of flavors will be investigated, and the computational models of the microcapsules will be optimized. The results of this project could supply useful data for selecting flavor microcapsules with proper microstures to satisfy the requirements of storage and application safety of different flavors. Determination of oxygen and water content in microcapsules has not been reported. This project uses indicators to measure the oxygen and water content inside microcapsules, which would be helpful for future investigation on microcapsules. There are abundant flavor resources in Hainan island. Both oxygen and water content in air are high on this island. Therefore, this project will theoretically guide efficient and safe application of local flavor resources.

微胶囊技术是对香料进行保护和控制释放的重要手段，但目前微胶囊化保护香料基本为定性结论，且微胶囊微结构（直径、微孔、壁厚、表面化学成分等）对透氧透水性能、香料稳定性和安全性的影响并未见报道。因此，本项目拟以不同结构纯香料物质和单方精油为芯材，以不同亲疏水性天然多糖为壁材，运用几种研究应用较为广泛的微胶囊制备方法制备香料微胶囊，测试微胶囊微结构以及香料成分变化，测试和模拟计算微胶囊的透氧透水传质系数，评价分析微胶囊微结构对香料稳定性及安全性的构效关系，建立微胶囊透氧透水计算结构模型，为筛选满足不同香料贮存及使用安全性的微胶囊结构及制备方法以及建立合理的微胶囊计算结构模型奠定理论基础。微胶囊内部氧、水含量测定未见报道，本研究新采用指示剂法测量微胶囊内部氧、水含量，对未来微胶囊研究将起到重要理论指导作用。海南省香料资源丰富，空气氧、水含量高，本研究对高效安全利用本地香料资源具有重要理论指导意义。

本项目以柠檬醛、肉桂醛、2-苯乙醇、β-紫罗兰酮等单方香料和茶树油、柠檬精油、玫瑰精油等复方香料为芯材，以甲基纤维素(MC)、壳聚糖(CTS)、海藻酸钠(AlG)、羧甲基壳聚糖(CMC)等多糖材料为壁材，通过复凝聚法、层层自组装、喷雾干燥等方法制备香料微胶囊，依据乳液电位及形貌、微胶囊含油率、包封率、形貌等指标，考察了MC/ALG/MC、MC/CTS/ALG、MC/ALG/CTS、ALG/CTS/MC、MC/CTS/ALG/MC、等20余种壁材体系下微胶囊的结构性能，确定了适合不同成分香料的最佳壁材及制备条件，并对微胶囊的结构（含油量、直径等）、热稳定性、吸水性能及释放性能进行了研究。以CoCl2为水分指示剂，建立了微胶囊吸水量与指示剂颜色变化间的量化数学公式，证实了CoCl2作为水分指示剂的可行性。以亚甲基蓝/二氧化钛/甘油/甲基纤维素为氧气指示剂，探讨了不同壁材膜的变色情况和屏氧效果。测试了不同壁材微胶囊在不同贮存条件（空气中、袋装、瓶装）和不同贮存氧气压力环境下，芯材成分随时间变化情况，分析了芯材成分变化原因。研究测试了不同壁材肉桂醛微胶囊中芯材在空气和真空环境中，在不同温度条件下的氧化降解速率及微胶囊内部氧气压力，得到氧气传递活化能，表明MC/ALG/MC、MC/CMC/ALG/MC为最佳壁材料。测试了壁材平板膜的透水透气性能，进一步证实MC/ALG/MC、MC/CMC/ALG/MC对水分和氧气的阻隔效果最优。建立了微胶囊理论计算结构模型，并模拟计算了不同壁材负载2-苯乙醇微胶囊的形成过程，以及体系浓度和微胶囊各组分相对含量对微胶囊聚集形态的影响，为后续利用模拟方法指导微胶囊制备、深入探讨分析微胶囊结构、透氧透水效率、香料稳定性及安全性的关系等奠定了基础方法及模型。本项目执行期间，已经公开发表论文20篇，其中SCI收录论文11篇、EI收录论文1篇，另有1篇已接收待发表，2篇正投稿返修中。申请国家发明专利1项。培养研究生4人。参加国际学术会议3次，完成1次口头报告和1次墙报展示。完成了项目研究目标。