Commercial neutral protease, with high purity levels and a strong ability to hydrolyze protein, was acquired from Beijing Solarbio Science & Technology Company (Beijing, China), which conforms to the Food Chemical Codex (FCC) and the food grade enzymes specification standards of light industry (QB/T1803-93). The fungal DNA kit was purchased from OMEGA Engineering (Connecticut, America); DEAE-Sepharose Fast Flow was obtained from Beijing Ruida Henhui Science & Technology Development Company (Beijing, China); and the Coomassie brilliant blue Kit was from Nanjing Jiancheng Bioengineering Institute (Nanjing, China). Polyethylene glycol 2000-0 (PEG-20M) was obtained from Chengdu Jinshan Chemical Reagent Company (Chengdu, China). Tris, Folin phenol, and Triton X-100 were purchased from Beijing Solarbio Science & Technology Company (Beijing, China). Rose Bengal medium was obtained from Beijing Aobox Biotechnology Company (Beijing, China). All the other chemicals were analytical grade.
The fermented broad beans were collected under high temperature in summer from an open-air natural fermentation workshop, where the average temperature of the fermentation pool reaches 55 °C.
The fermented broad beans were collected under high temperature in summer from an open-air natural fermentation workshop, where the average temperature of the fermentation pool reaches 55 °C.