Unraveling the core bacterial community responsible for quality and flavor improvement of the radish paocai during spontaneous fermentation

The effects of different varieties of radish on the quality and flavor of radish paocai are still elusive. Herein, this study aimed to compare the quality and flavor of radish paocai fermented by three kinds of radish, and further investigate the core bacterial community that mainly positively correlated with the quality and flavor improvement of paocai. As fermentation proceeded, pH and nitrite decreased, total acid and reducing sugar increased, and salinity showed a fluctuating decrease. Besides, LL had the highest content of reducing sugar and free amino acids, and CB had more organic acids and umami amino acids than other kinds of paocai. The bacterial community analysis confirmed that the variety of radish had little impact on bacterial succession, and Weissella, Lactobacillus, and Leuconostoc were found to be the core bacterial community that could promote the increase of organic acids, free amino acids, and volatile flavor compounds. In particular, Weissella was the biomarker on day 4 of fermentation, and Lactobacillus was the biomarker on day 7 in three kinds of radish paocai. Collectively, using different varieties of radish did not significantly induce change in the bacterial community of the radish paocai, although these radish paocai products presented different qualities and flavors.