脂质伴随物对亚麻籽油纳米乳液稳定性及吸收代谢的影响和调控机制

Nanoemulsion delivery system provides a new opportunity for improving the bioavailability of α-linolenic acid (ALA) in flaxseed oil (FO). The previous studies mainly focused on the effect of emulsifier and emulsifying method on the structure stability of FO nanoemulsion. However, the effect of lipid concomitant on the oxidation stability, absorption and metabolism of FO nanoemulsion and the potential mechanism are still not clear. In this project, FO with different contents of lipid concomitant is obtained by optimizing the processing technology, including hot-pressing and totally refining, cold-pressing and partly refining, microwave pretreatment plus subcritical fluid extraction. Microfluidic high pressure emulsification is used for FO nanoemulsion preparation. We focus on the partitioning behavior and association colloids construction of lipid concomitant on oil-water interface through the removal-restorative addition of lignans/polyphenols (polar), tocopherols (nonpolar), phytosterols/phospholipids /diacylglycerol/free fatty acids (amphiphilicity) in order to clarify the stabilization mechanism of lipid concomitant in multi-level. Moreover, the in vitro gastrointestinal digestion simulation, cells and animal experiments are carried to explore the mechanism of action of lipid concomitant on digestion, absorption and metabolic pathway of ALA in FO nanoemulsion. This project will not only enrich the basic theory of lipid nanocarriers, but also provide the theoretical basis for the increased bioavailability of plant-derived n-3PUFA.

纳米乳液递送体系为提高亚麻籽油（FO）中α-亚麻酸(ALA)生物利用度提供了新的契机。目前针对FO纳米乳液研究主要集中在乳化剂、乳化方式对体系结构稳定影响上，而脂质伴随物对乳液氧化稳定性、吸收代谢的影响及作用机制尚不清楚。本项目拟通过制油工艺（热榨全精炼→低温压榨适度精炼→微波预处理+亚临界流体萃取）优化，获得脂质伴随物含量差异显著的FO，采用微射流超高压均质法制备FO纳米乳液，进一步通过木酚素/多酚（极性）、生育酚（非极性）、植物甾醇/磷脂/甘油二酯/游离脂肪酸（双亲型）去除-恢复性添加，基于界面空间定位、联合胶束构建多层次阐释脂质伴随物影响FO纳米乳液稳定性的作用机理。借助体外胃肠道消化模拟实验、细胞及动物实验等手段，探讨脂质伴随物对FO纳米乳液中ALA消化吸收及代谢途径的影响及调控机制。本项目的实施对丰富脂质纳米载体基础理论和植物来源n-3PUFA高效摄入与利用提供理论依据。

本项目通过制油工艺优化获得脂质伴随物差异显著的亚麻籽油（FO）基础上，借助不同极性大小脂质伴随物去除-恢复性添加，基于空间定位、联合胶束构建、界面抗氧化多层次阐释脂质伴随物影响FO乳液稳定性的作用机理。进一步系统探讨脂质伴随物对FO乳液胃肠道消化、ALA转运和代谢转化的调控效应。主要研究成果包括：①通过热榨全精炼、低温压榨适度精炼、微波辅助低温压榨、亚临界流体萃取等制油工艺优化分析，筛选出内源性脂质伴随物具有显著差异的FO，并探究了内源性脂质伴随物对不同乳化剂构建的FO乳液稳定性的调控规律。其中植物甾醇、类胡萝卜素、多酚、环肽与乳液稳定性呈显著正相关；②基于油-水界面张力、界面定位、与乳化剂交互作用、自由基渗透等揭示了脂质伴随物对FO乳液稳定性的调控机制。其中木酚素结构单元和生育酚异构体在乳清分离蛋白或磷脂基乳液中表现出差异性的调控效应；③基于界面联合胶束构建揭示了内源性脂质伴随物构建的反胶束对FO及乳液稳定性的影响机理。其中具有表面活性的脂质伴随物构建的反胶束降低了脂质氧化稳定性，同时限制了生育酚的界面锚定；④基于界面理论阐释了内源性脂质伴随物对FO乳液胃肠消化、FFAs释放和吸收的调控作用。其中植物甾醇、多酚能够与蛋白质（粘蛋白和胃蛋白酶）发生非共价相互作用提高乳液消化稳定性，磷脂可促进脂肪酶界面吸附和激活提高FFAs释放；⑤借助大鼠淋巴插管实验和高脂喂养动物实验研究发现，纳米化明显增加了磷脂基FO乳液中ALA淋巴转运效率，而木酚素通过调控乳糜微粒组装速率、尺寸大小和脂质氧化水平，实现对ALA肠道增效吸收和局域性转化调控，并通过肝脏线粒体依赖的脂质代谢激活、脂质氧化抑制和ALA代谢转化调控，强化了FO对胰岛素抵抗的改善效应。本项目实施本项目实施进一步丰度了脂质纳米载运体系稳态化构建基础理论，同时也为植物源n-3 PUFA高效摄入与利用提供了理论依据。