燕麦乳浊体系中蛋白聚集行为与界面吸附对稳定性的影响机制

Oats got a lot of attentions due to its nutritional and healthy profile, especially cholesterol-lowering effect. Oat milk was popular as a new type of oat products with good taste, nutrition and convenience high-profile. Oat milk protein content is higher（≥1.0%), prone to aggregation and sedimentation during heating. Our previous research has found that when the system contains a certain amount of oil, the oat milk can form a good thermal stability system. But this mechanism is not clear. Based on this, the project intends to make oat milk system as the research object and carry out the following research: (1)In natural oat milk system, the structure evolution was revealed through the clear of the state and structure of protein aggregates ; (2)In the oil-in-water oat milk system, the interface characteristics and emulsifying ability of oat protein were studied from the qualitative/quantitative, phase/interface, macro/micro. compared with the differences of the protein aggregates formed from two systems, and the intervention mechanism was elucidated which the oil-water interface formation influence oat protein aggregates and interface adsorption behavior. The results reveals stability mechanism in high oil and protein oats milk system and improves the quality of oat products and provides theoretical guidance for corn beverage stability.

燕麦营养保健功能突出，其显著的降脂功效已获得世界公认。燕麦乳作为一种新型燕麦制品，因具有良好的口感、营养及方便性而倍受瞩目。但其内源蛋白质含量较高（≥1.0%），加热过程极易聚集、沉淀。本课题组前期研究发现，当该体系添加一定量外源植物油，则可形成良好的热稳定乳浊体系，但该体系的热稳定机制尚不清楚。基于此，本项目拟以燕麦乳浊体系为研究对象，开展如下研究：①天然燕麦乳浊体系中，蛋白聚集体的存在状态和结构特征，加热条件下燕麦蛋白的解离与重聚集情况，揭示燕麦蛋白热聚集过程的结构演变规律；②水包油型燕麦乳浊体系中，从定性/定量、宏观/微观、体相/界面等多个层次研究燕麦蛋白的界面特性和乳化能力，对比①②两种体系中蛋白聚集体形成的差异，进而阐明油-水界面的形成对燕麦蛋白体相聚集及界面吸附行为的干预机制，揭示高油、高蛋白燕麦乳浊体系的稳定机制。预期结果可为提升燕麦及相关谷物饮料的品质稳定性提供理论指导。

燕麦是一种营养与保健功能突出的谷物，将其加工成液态乳，不仅满足营养健康的需求，也增加了一种新的食用途径。燕麦乳蛋白含量较高，易发生聚集、沉淀、分层。我们前期研究发现当该体系中包含一定量油脂时，能够形成良好的热稳定体系，但这种自稳机制尚不清楚。因此本项目以真实体系与模拟体系中燕麦蛋白为研究对象，将蛋白聚集行为作为研究的关键点，首先明确燕麦蛋白乳体系中聚集体的存在状态和结构特性,，开展不同酶解条件、加热条件、环境因素下燕麦蛋白的结构演变规律；结果发现燕麦球蛋白的酸性亚基是聚集体的主要结构蛋白；当存在油水界面条件时，将燕麦蛋白界面吸附行为作为研究的关键点，系统研究了蛋白质在油-水界面上的吸附特性，界面蛋白组成等，结果显示pH值为酸性条件下极大影响体系的界面吸附，酚酸类成分与蛋白络合也导致界面失稳。对比不同加热条件下燕麦蛋白参与O/W界面吸附对体系蛋白聚集体的形成和稳定性的影响发现，加热过程中随温度升高蛋白聚集体开始解离，当温度超过球蛋白的变性温度后解离的蛋白亚基又重新形成聚集体。本项目突破现有研究对燕麦蛋白乳失稳与自稳机制认识不全、不深的局限性，从全新角度探索其结构与功能的相关性。通过本项研究，形成燕麦蛋白功能特性酶法改良技术，改善饮料加工过程中蛋白质引发的失稳问题，研究结果将为燕麦乳产品加工和新技术创新提供必要的理论指导，具有一定的产业应用意义。