蛋白质聚集状态影响蛋白质/多糖静电复合及界面/乳化特性的机制研究

As two of the most important food components, protein and polysaccharide in synergism can produce incomparable functionalities that individual components fail to provide. This is crucial to the research and development of novel composite food ingredients. The project deals with typical protein assemblies (e.g., globular protein, spherical nanoparticle, and fibril) existing during food processing, and carries out a comparative study on the impact of protein assembling states on protein/polysaccharide electrostatic complexation and the resultant interfacial/emulsifying functionalities. The mechanism associated therein will be elucidated, and the principle and methodology to control the functionalities will be established. Taking beta-lactoglobulin/sodium alginate (BLG/ALG) as a representative protein/polysaccharide system, the study involves controlled preparation and characterization of BLG assemblies of different types, and examines the influence of BLG assembling states on the electrostatic complexation, phase diagram and complex structure of BLG/ALG. Focused on soluble electrostatic complexes, the interfacial behaviors of BLG/ALG are investigated by measuring adsorption kinetics, interfacial mechanical properties and microstructures at the oil-water and air-water interfaces. Using a model oil-in-water emulsion, the emulsifying activities and emulsion stabilities of BLG/ALG electrostatic complexes are evaluated. Furthermore, the correlation between protein assembling states, electrostatic complexation, interfacial behaviors, and emulsifying characteristics is established, based on a bottom-up approach. The knowledge gained in the project is expect to extend the theory of protein/polysaccharide electrostatic complexation, and is of technological importance for its relevant applications in the food industry.

作为重要的食品组分，蛋白质/多糖协同可产生单一组分不可比拟的功能特性，对开发新型的食品复合配料技术至关重要。本项目针对食品加工中常见的蛋白质聚集体（球状分子、球状纳米颗粒、微纤维），对比研究蛋白质聚集状态对蛋白质/多糖静电复合及其界面、乳化特性的影响，阐明内在机制并建立调控理论和方法。以beta-乳球蛋白/海藻酸钠（BLG/ALG）为代表性体系，可控制备和表征不同类型的BLG聚集体，考察BLG聚集状态对BLG/ALG静电复合行为、相图和复合物结构的影响；聚焦可溶性静电复合物，测定BLG/ALG在气水和油水界面上的吸附动力学、界面力学性能和微结构；利用模型食品乳液体系，评价BLG/ALG复合物的乳化活性和乳液稳定性；自下而上，建立蛋白质聚集状态-蛋白质/多糖静电复合-界面行为-乳化特性四者的关联。研究结果将丰富蛋白质/多糖静电复合的理论内涵，对其食品工业应用具有重要的指导意义。

蛋白质和多糖作为关键的食品组分，常混合共存于各类食品之中，深入理解蛋白质/多糖间的协同作用对发展新型的复合食品配料技术具有重要意义。本项目以β-乳球蛋白（β-lg）/κ-卡拉胶和乳清分离蛋白（WPI）/海藻酸钠（ALG）为研究体系，对比研究了未变性蛋白分子、球状纳米颗粒、微纤维三种聚集状态对蛋白质/多糖静电复合相图的影响；聚焦界面和乳化特性，考察了蛋白质聚集状态对静电复合物功能特性（凝胶、乳化、发泡）的影响，自下而上建立了蛋白质聚集状态-蛋白质/多糖静电复合-界面行为-乳化特性四者的关联，阐明了内在影响机制并建立调控理论和方法。将研究体系拓展至乳清分离蛋白纤维（WPF）/阿拉伯胶（GA）复合体系，研究了WPF/GA静电复合行为及复合物乳化特性。重要研究结果和科学意义为：.（1）利用可控热处理，制备了球状β-乳球蛋白（NGBLG）及其纳米颗粒聚集体（NPBLG）和微纤维（FBLG），实现了对蛋白质微纳米聚集体形貌和尺寸的精准调控。.（2）绘制了β-lg微纳米聚集体/κ-卡拉胶及WPI/ALG复合相图，发现β-lg聚集状态对分子内可溶性复合物的相区无明显影响，而ALG分子量的降低使WPI/ALG相图中分子内可溶性复合物相区减少。.（3）β-lg聚集体的界面特性不仅与蛋白聚集体的疏水性有关，还与聚集状态和尺寸有关，发现FBLG的表面压力最大，在气水界面倾向于形成网状结构，具有更好的界面稳定作用。.（4）β-lg/κ-卡拉胶静电复合对卡拉胶的凝胶性能有显著改善作用，FBLG/κ-卡拉胶可溶性复合物的泡沫稳定性和乳化性最好，WPF/GA不溶性复合物制备的蛋黄酱类似物感官评分与自制蛋黄酱相似，该发现对拓展蛋白聚集体的功能应用具有重要意义。.围绕上述研究结果，在ACS Applied Materials & Interfaces、Biomacromolecules、Food Hydrocolloids、Carbohydrate Polymers等权威杂志上发表SCI第一标注论文10篇，申请专利3项，培养硕士研究生6名。