**2. Materials and Methods**

### *2.1. Materials*

Split peas were purchased from Foshan Jinnuoyi Processing Factory of Agricultural Products (Foshan, China); the protein content was 21.12% (6.25 of N, wet weight). Grass carp were purchased from the local fish market in Zhanjiang City, Guangdong Province. The gills, heads, tails, bones, and blood were removed, leaving only the white muscles on the back, which were retained and frozen at a low temperature. The fish muscles were brought back to the laboratory and stored at −20 ◦C; the protein content was 18.27% (6.25 of N, wet weight). Electrophoresis reagents were purchased from Beyotime Biotechnology Co., Ltd. (Shanghai, China). The ANS fluorescence probe was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (Shanghai, China). Other reagents were of analytical grade and were ordered from the Guangzhou Chemical Reagent Factory (Guangzhou, China).
