The formation mechanism of sufu gels fermented by mucor racemosus during pre-fermentation

Sufu, a traditional fermented soybean product, known for its cheese-like texture, has not been extensively studied regarding the mechanisms responsible for the formation of this unique texture in sufu gels. In order to explore this phenomenon, an analysis was conducted on the texture, physicochemical properties, and microstructure of sufu gels fermented by mucor racemosus at different intervals. The findings indicated no significant difference in water holding capacity (WHC) of sufu gel at 0 h, 24 h, and 48 h, but a notable increase in WHC was observed at 72 h and 96 h ( p<0.05 ). The hardness of sufu gel at 72 h and 96 h was found to be low, with values of 4.8± 0.56 N and 4.99± 0.54 N, respectively, indicating a soft texture of sufu. The peak of protease activity at 48 h was 38.19 U/g. Following fermentation for 24 h and 48 h, the secondary structure of sufu gel was predominantly composed of β-sheet, while α-helix was the primary secondary structure at 72 h and 96 h. Analysis using the scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) analysis revealed the network-like structures present in sufu gel. These findings offer valuable insights for enhancing gel properties and sensory characteristics.