基于异型聚集效应构建乳状液微聚集体及其影响流变特性机理研究

The content of fat is decreased in the reduced-fat food products for the need of health, but which may decrease the rheological property. Food emulsion can be used to replace part of fat to improve the rheological property of food. The formation of micro-cluster based on controlled hetero-aggregation is a promising method to have desirable rheological property. The present project is to study the fabrication of emulsion micro-cluster based on controlled heteroaggregation and the effect mechanism of its rheological property. Different particle size of micro-cluster was fabricated by mixed β-Lactoglobulin (β-Lg)-coated lipid droplets with flaxseed gum (FG)-coated lipid droplets. The rheological property was characterized by micro-rheological and shear rheological techniques. The relationship between particle size distribution and rheological property will be discussed. The unadsorbed β-Lg and FG of the emulsion droplets will be washed. The influence of unadsorbed β-Lg and FG on the rheological property of the micro-cluster will be analyzed. The thermodynamics and kinetics of interactions between unadsorbed β-Lg, FG and droplets will be measured by surface plasmon resonance imaging system and isothermal titration microcalorimetric techniques. The three-dimensional microstructure of the micro-clusters will be observed. The purpose of the study is to propose the schematic of the fabrication of emulsion micro-cluster based on controlled heteroaggregation and to elucidate the effect mechanism of its rheological property. Theoretically, this research can lay the foundation for the fabrication of emulsion micro-cluster based on controlled heteroaggregation. Furthermore, it can also provide a new technique approach for designing novel reduced-fat food delivery system.

低脂食品需减少脂肪含量以适应健康需求，但会劣化食品流变特性，乳状液替代部分脂肪可改善其流变特性。控制异型聚集效应形成微聚集体，是提高食品乳状液体系流变特性的新途径。本项目针对异型聚集效应构建微聚集体及其影响流变特性的科学问题，拟以β-乳球蛋白（β-Lg）微滴与亚麻籽胶（FG）微滴为研究对象，①构建不同尺寸分布的微聚集体，结合微聚集体的微流变与剪切流变特性分析，解析微聚集体尺寸分布与流变特性之间的关系；②洗脱β-Lg微滴与FG微滴中未吸附β-Lg、FG，解析未吸附分子对微聚集体流变特性的影响；③基于表面等离子体共振成像系统与等温滴定微量热技术，探索未吸附β-Lg、FG及微滴间相互作用的动力学过程与吸附热力学，结合微聚集体三维空间网络结构分布，构建微聚集体形成模型，揭示异型聚集效应影响微聚集体流变特性机理。本项目可望丰富异型聚集效应构建微聚集体理论，为研制新型低脂食品载体提供理论和技术基础。

乳状液替代部分脂肪改善其流变特性对开发减脂食品具有重要的意义。控制异型聚集效应形成微聚集体，是提高食品乳状液体系流变特性的新途径。本项目系统研究了乳清蛋白微滴与亚麻籽胶微滴基于异型聚集效应构建微聚集体及其流变学特性。采用微流变、冷冻扫描电镜等前沿技术手段解决微聚集体领域的关键问题。明确了不同亚麻籽胶微滴含量对微聚集体稳定性及流变学特性的影响；探明了未吸附乳化剂（乳清蛋白和亚麻籽胶）影响微聚集体的空间结构及流变学特性的机理；考察了不同油相含量对单一乳状液和微聚集体稳定性及流变特性的影响；明确了微聚集体提高乳状液的物理稳定性与流变特性的机理。主要结果如下：.（1）乳清蛋白微滴含量显著影响乳清蛋白-亚麻籽胶乳状液微聚集体的物理稳定性及流变特性。40%乳清蛋白微滴-60%亚麻籽胶微滴构建的微聚集体具有较好的稳定性和较高流变学特征。冷冻扫描电镜微观结构表明：微聚集体中游离乳清蛋白分子包裹在亚麻籽胶微滴表面，游离亚麻籽胶分子上缔合了乳清蛋白微滴。.（2）通过洗脱重塑微聚集体研究表明，游离相影响微聚集体的稳定性，游离乳清蛋白、亚麻籽胶显著提高微聚集体的粘度。重组微聚集体的结构疏松，导致洗脱后微聚集体的稳定性及流变学特性降低。.（3）油相含量对构建乳清蛋白-亚麻籽胶乳状液微聚集体的物理稳定性及流变特性影响表明，随着油相含量的增加，微聚集体的稳定性及流变学特性逐渐降低。低油相（10%和15%）的微聚集体，由于游离乳清蛋白、亚麻籽胶的存在，具有高流变和较好的稳定性，高油相（20%和30%）微聚集体由于游离乳清蛋白、亚麻籽胶的减少，使得微聚集体的结构不足以维持高流变和高稳定性的特征。.（4）通过对比微聚集体、层层组装与直接混合技术对乳状液稳定性的影响表明，微聚集体具有较好的稳定性，界面移动速度较慢且最终的整体透光率较低；流变学特性分析可知，微聚集体具有高流变特征。.明确了乳状液微聚集体基于游离相与微滴间缔合相互作用，形成特定空间网络结构是维持高稳定性与高流变特性的机制。.本研究为开发食品脂质替代物奠定一定的理论基础。