Lysozyme (LYS) and κ-carrageenan (κ-CRG) are important components widely used in food and pharmaceutical products. In this work, we investigated the interactions in the aqueous mixtures of LYS and κ-CRG and the structural transformation of the LYS/κ-CRG complexes. When co-soluble polymers and soluble complexes are formed in near-neutral environment, insoluble complex coacervates are formed at lower pHs. Significant accumulation and size expansion of coacervate particles occur at pH = 4.0 where maximum interactions are presented at the mixing ratio of LYS/κ-CRG = 2:1. The coacervate system is flexible to rearrange to reach a charge balanced state by gradual protonation of LYS and κ-CRG. Addition of NaCl up to 50 mM weakens the electrostatic attractions among the aggregates through counterion binding. Thermal stability of LYS by forming complex coacervates differs from that in water, and effective protection of protein is achieved as the unfolding temperature is increased by 9 °C.

溶菌酶（LYS）和κ-卡拉胶（κ-CRG）是广泛用于食品和药品的重要成分。在这项工作中，我们研究了LYS和κ-CRG的水性混合物中的相互作用以及LYS /κ-CRG配合物的结构转化。当在近中性环境中形成共溶性聚合物和可溶性络合物时，在较低的pH值下会形成不溶性络合物凝聚层。凝聚层颗粒在pH = 4.0时会发生明显的堆积和尺寸膨胀，其中最大相互作用以LYS /κ-CRG= 2：1的混合比出现。凝聚层系统通过LYS和κ-CRG的逐渐质子化，可以灵活地重排以达到电荷平衡状态。通过抗衡离子结合，添加高达50 mM的NaCl会削弱聚集体之间的静电吸引力。