长链n-3多不饱和脂肪酸纳米乳液无定形态固体分散体的构建及生物利用度研究

There is a growing interest in developing functional foods and beverages containing omega-3 PUFAs due to their health benefits in preventing cardiovascular disease. However, the poor water solubility and the oxidative instability of omega-3 PUFAs limits their incorporation into foods and beverages. The design of food grade solid nanoemulsions dispersion system to encapsulate omega-3 PUFAs is one of the most effective and promising way to enhance its solubility and environmental stability. The solid nanoemulsions for encapsulation omega-3 PUFAs will therefore be fabricated using different types of low energy techniques coupled with spray drying solid dispersion technique. The impact of food grade surfactants properties, the existence forms of fish oil omega-3 fatty acids, and.their compositional variations along with water phase on the formation of nanoemulsions will be fully investigated. The impact of solid carrier’s molecular weight and polarity, and inlet-outlet temperature of spray drier on the crystalline properties and functionality of solified nanoemulsions will also be studied. The structure-function relationship between structure characteristics of matrix nanoemulsions (e.g., concentration, particle size and surface charge), the solid nanoemulsions (e.g., morphology and crystal type), and the physicochemical properties of solid nanoemulsions will be developed through the characterization of nanoemulsions characteristics and corresponding solid nanoemulsions functions. The optimal solid nanoemulsions composition and low energy approach which could maximize omega-3 PUFAs bioaccessibility will be sorted out using in vitro digestion model and cell culture absorption model. The results gained from this project will provide new methods of formulating amorphous solid nanoemulsions for encapsulation other bioactive lipids. It will also enable the rationalization of low energy method coupled with solid dispersion technique for solid nanoemulsions matching the requirement of specific functions for food and beverage products.

长链n-3 多不饱和脂肪酸（LC n-3 PUFA）水溶性差及化学性质不稳定是其难以工业化应用的主要原因。本项目将运用多种低能量方法制备负载LC n-3 PUFA食品级水包油纳米乳液，并结合固体分散技术实现纳米乳液的无定形态固化。具体研究表面活性剂性质、LC n-3 PUFA食品级水包油纳米乳液存在形式，及与水相比例对低能量方法制备纳米乳液的影响，同时研究不同分子量及极性固化载体及喷雾干燥条件对固体分散体晶体结构及功能的影响。最终通过对纳米乳液粒径大小、表面电荷等结构，纳米乳液固体分散体晶型结构、表面形貌等性质，与纳米乳液固体分散体物化稳定性等功能的表征，建立纳米乳液-无定形态固体分散体结构功能关系。在此基础上，通过体外消化和细胞模型研究经本体纳米乳液及其固体分散体负载的omega-3生物利用度，寻找能有效提高固体分散体生物利用度的纳米乳液组成及低能量制备方法。

项目运用低能量方法制备了负载LC n-3 PUFA食品级水包油纳米乳液，结合LC n-3 PUFA食品级水包油纳米乳液存在形式及与水相比例对低能量方法制备纳米乳液的影响，研究了不同分子量及极性固化载体及喷雾干燥条件对固体分散体晶体结构及功能的影响。通过不同pH制备条件对纳米乳液粒径大小、表面电荷等结构，纳米乳液固体分散体晶型结构、表面形貌等性质，与纳米乳液固体分散体物化稳定性等功能的表征，研究了纳米乳液-无定形态固体分散体结构功能关系。研究发现乳液整体的正电荷PPI（-NH4+）可以与阴离子SBP（-COO-）在pH小于4.5时产生静电吸引并形成复合凝聚物。冻干复合凝聚物的这种形态变化证实了静电相互作用的强度在不同的pH值下是不同的，结果证实了复合凝聚体壁-基质间非共价相互作用的关键作用更依赖于pH值的变化。在满足生物聚合物之间处于最佳强度的静电相互作用的情况下，通过复合凝聚得到的喷雾干燥LC n-3 PUFA粉具有更好的封装效率和理化性质。因此，选择合适的壁材对LC n-3 PUFA喷雾干燥粉的理化性能的提高十分关键。相对于基质乳液而言大尺寸LC n-3 PUFA和小尺寸LC n-3 PUFA的游离脂肪酸释放率均呈现出先迅速增加然后缓慢上升的趋势。经37 ℃模拟肠道消化1 h后，小尺寸LC n-3 PUFA乳液的脂肪酸释放率明显大于大尺寸LC n-3 PUFA乳液，这与小尺寸乳液具有较大表面积能够更容易与消化液作用释放出游离脂肪酸。大尺寸LC n-3 PUFA乳液液滴尺寸和凝聚行为限制了脂肪酸分配到混合胶束中，部分限制了其在消化体系中的生物利用度。尽管如此，LC n-3 PUFA乳液的消化特性仍然较基质乳液更好，这表明低能量LC n-3 PUFA乳液具备较高的生物利用度，可实现其在消化系统中的快速供能及营养功效。本研究作为在食品中添加LC n-3 PUFA 的一种角度和思路，有望对功能性油脂的开发和亲脂性生物活性化合物微胶囊化和利用提供一些新的视角和产业开发支撑。