*Article* **A Comparative Functional Analysis of Pea Protein and Grass Carp Protein Mixture via Blending and Co-Precipitation**

**Xiaohu Zhou 1,2,3,4, Chaohua Zhang 1,3,5,\*, Wenhong Cao 1,3,5, Chunxia Zhou 1,3,5, Huina Zheng 1,3,5 and Liangzhong Zhao 2,4**

	- <sup>4</sup> Hunan Provincial Key Laboratory of Soybean Products Processing and Safety Control, Shaoyang 422000, China
	- <sup>5</sup> Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian 116034, China

**Abstract:** Currently, the application of protein mixture derived from plants and animals is of great interest to the food industry. However, the synergistic effects of isolated protein blends (BL) are not well established. Herein, the development of a more effective method (co-precipitation) for the production of protein mixtures from pea and grass carp is reported. Pea protein isolate (PPI), grass carp protein isolate (CPI), and pea–carp protein co-precipitates (Co) were prepared via isoelectric solubilization/precipitation using peas and grass carp as raw materials. Meanwhile, the BL was obtained by blending PPI with CPI. In addition, the subunit composition and functional properties of Co and BL were investigated. The results show that the ratios of vicilin to legumin α + β and the soluble aggregates of Co were 2.82- and 1.69-fold higher than that of BL. The surface hydrophobicity of Co was less than that of BL, PPI, and CPI (*p* < 0.05). The solubility of Co was greater than that of BL, PPI, and CPI (*p* < 0.05), and the foaming activity was higher than that of BL and CPI (*p* < 0.05) but slightly lower than that of PPI. In addition, based on the emulsifying activity index, particle size, microstructure, and viscosity, Co had better emulsifying properties than BL, PPI, and CPI. The study not only confirmed that co-precipitation was more effective than blending for the preparation of mixed protein using PPI and CPI but also provided a standard of reference for obtaining a mixture of plant and animal proteins.

**Keywords:** pea; protein co-precipitates; protein blends; surface hydrophobicity; emulsifying properties
