基于微胶化多糖诱导高内相乳液的功能因子增溶与稳态化作用机制研究

Development of food delivery systems is highly potential to realize the stabilization, controlled delivery and enhanced absorption of food nutraceuticals. However, the loading contents of nutraceuticals in the food delivery systems are generally low, which limits their application in the scientific researches and industrial production. Our previous study found that the polysaccharide microgels prepared through crosslinking chitosan with genipin had super interfacial stabilization capability, which could emulsify 90% of oil under very low microgel concentrations, to form the high internal phase emulsions (HIPEs). The HIPEs were applied to encapsulate and load liposoluble nutraceuticals, which could increase their loading contents and chemical stability under different food processing conditions. Based on the previous work, we will investigate systematically the effects of different fabrication factors on the structure and physicochemical properties of the chitosan microgels; evaluate their safety for oral administration; prepare the microgel stabilized HIPEs and optimize their preparation methods for loading liposoluble nutraceuticals; characterize the distribution of the chitosan microgels with different physicochemical properties and the encapsulated liposoluble food nutraceuticals in the oil phase, water phase and their interface inside the HIPEs, thus to clarify the stabilization mechanism of the HIPEs, as well as its mechanism for increasing the loading contents of the liposoluble nutraceuticals. The stability of the encapsulated food nutraceuticals will be further investigated under different processing conditions. Then, the protection mechanism of the HIPEs on the encapsulated liposoluble nutraceuticals will be studied based on the distribution of the chitosan microgels and the encapsulated liposoluble food nutraceuticals in HIPEs; the protection effect of the HIPEs against light and heat; the metal ions adsorption effect of the polysaccharide microgel skeleton, as well as the antioxidant activity of the chitosan microgels. The outcomes of this project will provide a new and effective approach to increase the loading contents and stability of liposoluble nutraceuticals.

构建食品载体有望在解决功能因子的稳态保持、递送控制和吸收增效方面实现突破。但是，载体中功能因子的载量普遍较低，制约了相关的基础研究和产业化应用。我们构建了一种多糖微胶，发现其具有超强乳化能力，在低浓度下，能够稳定90%的油相，形成高内相乳液，显著地提高了功能因子的载量和稳定性。在此基础上，本课题拟系统地研究不同制备条件对多糖微胶理化性质的影响；评估多糖微胶的食用安全性；优化由多糖微胶稳定的高内相乳液负载脂溶性功能因子的制备条件；表征不同理化性质的多糖微胶和所负载的功能因子在乳液油、水两相及其界面上的分布，阐明乳液的稳定与增溶机制；进一步地研究乳液中的功能因子在不同加工条件下的稳定性，从多糖微胶和功能因子的分布状态、高内相乳液的光屏蔽功能、热稳定性、乳液中多糖骨架对金属离子的吸附能力和抗氧化活性等方面，探究其增强功能因子稳定性的作用机制。本研究将为增强脂溶性功能因子的载量和稳定性提供依据。

构建食品载体有望在解决功能因子的稳态保持、递送控制和吸收增效方面实现突破。但是，载体中功能因子的载量普遍较低，制约了相关的基础研究和产业化应用。高内相乳液是指乳液体系中内相（分散相）的比列超过几何极限值74%的乳液体系。其内相（分散相）液滴之间发生挤压和变形，呈现出多边形的形貌。以水包油（O/W）型高内相乳液为例，其独特的高油相比例为增溶脂溶性功能因子，提高其负载量提供了依据。形成食品高内相乳液的关键在于构建独特的食品级界面稳定剂。本项目系统地研究了京尼平交联壳聚糖微胶颗粒、网络微凝胶化食品多糖、界面高负载水溶性多酚体系、线状蛋白质有序聚集体（动物源、植物源）等作为界面稳定剂、构建高内相乳液、显著地提高了脂溶性类胡萝卜素类的包埋负载量及其加工稳定性的作用及其机制。在异质化乳液体系负载脂溶性功能因子的基础上，本项目又研究了食品组分有序组装的同质化水凝胶及其高负载水溶性功能因子及促进健康作用和机制。重要研究结果有：（1）发现了京尼平交联壳聚糖，造成多糖分子链塌缩，形成形貌越发规整、尺寸不断减小、分布更加均一的壳聚糖微胶颗粒；亲水性不断减小、亲油性不断增大，在油水界面分布的总能量平衡位置越接近于多糖微胶球体直径所在平面；多糖微胶以低于百分之一的浓度实现了同样的乳化效果，具有100倍以上的剂量优势，显著地提高了类胡萝卜素（β-胡萝卜素、番茄红素、叶黄素等）在乳液体系中的负载量10-200倍，增强其对紫外光、热处理、金属离子和过氧化氢的稳定性。（2）发现了不同电荷密度的多糖（海藻酸钠、卡拉胶、低甲酯化果胶、高甲酯化果胶）与蛋白质纤维相互作用，形成了稳定分散的网络微凝胶化食品多糖，增强高内相乳液地稳定性和强度。（3）构建了界面负载高载量水溶性多酚、油相负载高载量脂溶性叶黄素的高内相乳液体系，显著地提高了这两类功能因子的稳定性。（4）发现了动物源（鸡蛋溶菌酶）和植物源（豌豆蛋白）的蛋白质线状有序聚集体（蛋白质纳米纤维）的形成机制及其乳化性能，稳定高内相乳液，增溶和稳态化类胡萝卜素。（5）阐明了茶叶多酚类与蛋白质纤维的相互作用机制及其缓解肠道炎症、抑制高脂膳食诱导肥胖的作用机制。以第一/通讯作者在ACS Nano（IF5year 18.022），Biomaterials Science（IF5year 7.699）等发表SCI论文11篇，申请专利5项，获江苏高校科学技术成果二等奖。