Ovalbumin (OVA) is a good emulsifier; however, its emulsifying properties are easily affected by food components. In this study, tannic acid (TA) was used as a model polyphenol to interact with OVA. The OVA-TA complexes were characterized with circular dichroism, dynamic light scattering and interfacial tension measurements. The emulsions stabilized by OVA and OVA-TA were analysed by droplet size measurements. The results indicated that TA could bind well with OVA. Generally, the surface activity of OVA decreased after binding with TA due to the sheltering of the hydrophobic groups of OVA, decreasing the emulsion capacity of OVA. However, the particle size and interfacial tension of the OVA-TA complexes at pH 5.0 were significantly smaller than those of free OVA due to reduced aggregation from increased electrostatic repulsions. Therefore, the stabilities of the emulsions containing TA were improved at pH values near the isoelectric point (pH 4.75) of OVA. Heat treatment decreased the particle sizes of OVA-TA. On the other hand, heating could increase the interfacial tension, decreasing the emulsifying properties of OVA. Our work provides new insights into the influence of polyphenols on the emulsion efficiency of OVA.

卵清蛋白（OVA）是一种很好的乳化剂；但是，它的乳化性能很容易受到食品成分的影响。在这项研究中，单宁酸（TA）被用作模型多酚与OVA相互作用。通过圆二色性，动态光散射和界面张力测量来表征OVA-TA配合物。通过液滴尺寸测量来分析通过OVA和OVA-TA稳定的乳液。结果表明TA可以与OVA很好地结合。通常，由于与OVA的疏水基团的遮蔽，OVA的表面活性在与TA结合后降低，从而降低了OVA的乳液容量。然而，由于静电排斥力的增加，聚集减少了，在pH 5.0时，OVA-TA复合物的粒径和界面张力明显小于游离OVA。所以，在接近OVA等电点（pH 4.75）的pH值下，含TA乳液的稳定性得到改善。热处理减小了OVA-TA的粒度。另一方面，加热会增加界面张力，降低OVA的乳化性能。我们的工作为多酚对OVA乳液效率的影响提供了新的见解。