多尺度乳状液微聚集体构建、理化稳定机制及控释规律解析

The design of good delivery systems for nutrients to protect them from degradation and to improve their bioavailability is the aim of the development of functional food. The formation of multi scale micro-cluster based on controlled heteroaggregation is a promising method to control the release, target the delivery, and inhibit unfavorable chemical reactions of many nutrients. The multi scale micro-cluster may have an appreciable influence upon the physicochemical stabilities and the release of nutrients in the digestive tract. The multi scale micro-cluster was fabricated by mixing cationic lactoferrin (LF)-coated DHA droplets and soybean protein isolate (SPI)-coated DHA droplets (nano and micro scale, respectively). The formation rule of LF-DHA/SPI-DHA multi scale micro-cluster was established based on the relationship between droplet size distribution and physical stability. The droplet interaction, three-dimensional network, microrheology, and Brown motion of multi scale micro-cluster were determined to obtain its mechanism of the physical stability. The relationship between the droplet size, structure, oxidation of unadsorbed and interfacial protein, degradation and changes of volatile compounds of DHA were established. The aim was to obtain the mechanisms of the chemical stability of multi scale LF-DHA/SPI-DHA micro-cluster. The in vitro digestion of the multi scale LF-DHA/SPI-DHA micro-cluster was studied and modulated by changing particle size and structure. Theoretically, the research can lay the foundation for the fomration of multi scale emulsion micro-cluster based on controlled heteroaggregation. In addition, it can also provide a new technique approach for designing novel functional food delivery system.

提高功能因子输送载体稳定性与生物利用率，是功能食品发展亟需解决的难点问题。控制异型聚集效应形成多尺度乳状液微聚集体，是实现功能因子稳态化的新途径。针对多尺度乳状液微聚集体提高功能因子理化稳定性与控释的科学问题，拟以“纳米-纳米、微米-微米”级乳铁蛋白-DHA与大豆分离蛋白-DHA乳状液为异型微滴，构建多尺度LF-DHA/SPI-DHA乳状液微聚集体，①基于微聚集体尺寸分布与物理稳定性，探索多尺度微聚集体形成规律；②结合微滴间热力学、动力学相互作用、三维空间网络结构、微流变与布朗运动轨迹分析，探明多尺度微聚集体物理稳定机制；③建立DHA氧化降解、关键风味物质变化与尺寸分布、空间结构、界面与游离蛋白氧化之间的关系，阐明多尺度微聚集体化学保护作用；④研究体外模拟消化与释放动力学，揭示多尺度微聚集体控释规律。本研究可望丰富异型聚集效应构建微聚集体理论，为研制新型功能因子输送载体提供理论和技术基础。

提高功能因子输送载体稳定性与生物利用率，是功能食品发展亟需解决的难点问题。控制异型聚集效应形成多尺度乳状液微聚集体，是实现功能因子稳态化的新途径。本项目针对多尺度乳状液微聚集体提高功能因子理化稳定性与体外模拟消化的科学问题，以“纳米-纳米、微米-微米”级乳铁蛋白（LF）-DHA与大豆分离蛋白（SPI）-DHA乳状液为异型微滴，构建多尺度LF/DHA-SPI/DHA乳状液微聚集体，基于微聚集体尺寸分布与物理稳定性，探索多尺度微聚集体形成规律；明确了微滴间静电相互作用与空间位阻效应、三维空间网络结构对多尺度微聚集体物理稳定性的影响；研究了多尺度DHA乳状液微聚集体氧化产物及关键风味物质变化，明确了多尺度DHA乳状液微聚集体的化学稳定性，探究多尺度乳状液微聚集体理化稳定机制；采用体外模拟消化模型，揭示了多尺度微聚集体消化规律。.主要结果如下：（1）构建了LF/DHA-SPI/DHA乳状液微聚集体，LF/DHA乳状液与SPI/DHA乳状液形成微聚集体（pH 6.0）最佳比例为1:1，微观结构分布均匀，形成特定三维空间网络结构，LF/DHA-SPI/DHA微聚集体显著提高DHA乳状液的物理稳定性。（2）不同尺寸LF/DHA、SPI/DHA微滴通过异型聚集可以形成微聚集体，不同尺寸微滴聚集均有特定稳定区，纳米级尺寸微滴所构建的微聚集体理化稳定性较好。（3）LF/DHA-SPI/DHA微聚集体具有一定的刚性，显著提高了pH耐受稳定性。转谷氨酰胺酶处理提高微聚集体的空间位阻作用，提高其稳定性。证明了静电相互作用与形成的特定三维空间网络结构产生的位阻效应，是影响DHA乳状液微聚集体的物理稳定机制。（4）多尺度LF/DHA-SPI/DHA乳状液微聚集体化学稳定性提高，微聚集体的一级与二级氧化产物含量均降低，微聚集体产生的关键挥发性物质己醛、（E, E）-2,4-庚二烯醛含量显著降低。空间位阻作用有效减少与自由基及过渡态金属离子的接触，是多尺度LF/DHA-SPI/DHA乳状液微聚集体的化学稳定机制。（5）DHA乳状液微聚集体促进蛋白质在胃液阶段的消化，提高DHA脂肪酸释放率，促进脂质消化。.本研究可望丰富异型聚集效应构建微聚集体理论，为研制新型功能因子输送载体提供理论和技术基础，在食品、化妆品及医药行业具有广阔的应用前景。