Effect of temperature on the quality and microbial community during Daocai fermentation

Temperature has a profound influence on microbial community structure and microbial metabolic products, making significant contributions to the quality of fermented products. Therefore, it is hypothesized that temperature will affect the microbial community structure during the fermentation process of Daocai, and the microbial community structure will affect the changes in physicochemical indicators, biogenic amine content, and volatile flavor compounds of Daocai. Firstly, sensory evaluations of color, aroma, taste, and crispness were conducted on Daocai samples fermented under different temperature conditions to determine the preferred temperature for temperature-controlled natural fermentation. Next, the differences in microbial community structure between samples from temperature-controlled and non-temperature-controlled natural fermentation of Daocai were determined by high-throughput sequencing. Subsequently, the differences in physicochemical indicators, biogenic amine content, and volatile flavor compounds in the Daocai samples with different fermentation methods were determined through testing. Finally, the correlation between microbial community structure and physicochemical indicators, biogenic amine content, and volatile flavor compounds was determined. The basic information of the 10 most abundant flavor compounds we detected is shared. High temperature (28°C) increases the relative contents of Ethyl Acetate, Methyl Acetate, 3-Methyl-1-butanol, Ethanol, Propanal, and 3-Pentanone, and decreases the relative contents of (E)-2-Hexenol, Acrolein, and (E)-2-Pentenal.