The Fermentation Law of Biogenic Amines in the Pre-Fermentation Process Is Revealed by Correlation Analysis

Sufu is a traditional Chinese condiment with a distinctive flavor. The umami characteristics are primarily attributed to the hydrolysis of proteins, which produces amino acids and biogenic amines (BAs). Excessive levels of BAs can pose health risks, leading to adverse effects, such as headaches, digestive disorders, and abnormal blood pressure. However, the mechanisms leading to the formation of BAs in fermented bean curd remain insufficiently explored. To explore this phenomenon, an analysis was conducted on the texture, physicochemical properties, and BA content dynamic changes of sufu, fermented with Mucor racemosus, at different intervals, by high-performance liquid chromatography-mass spectrometry (HPLC-MS). During the fermentation process, the total biogenic amines exhibited a downward trend, with levels decreasing from 60.66 to 38.19 mg/kg. Spermidine, spermine, and cadaverine were identified as the main biogenic amines produced during the fermentation process. At 0 h and 24 h, spermidine levels significantly decreased (p < 0.05), but no significant differences were observed at 48 h and 72 h. At 96 h, spermidine levels significantly decreased again (p < 0.05). There was a positive relationship between the bioamines and water content and a negative correlation with soluble protein levels. Additionally, low pH inhibits the formation of BAs, while a soft texture was found to increase their production. The results of this study also confirmed the mechanism of BAs formation. These findings offer valuable insights into the safety and quality control of Mouding sufu by clarifying the BA dynamics during pre-fermentation.