Abstract: In this study, 16S rRNA high-throughput sequencing was used to study the succession of microbial community during the natural fermentation of tilapia surimi. The results showed that Firmicutes and Proteobacteria were the major phyla in the whole fermentation process, especially Firmicutes, whose relative abundance gradually increased with fermentation time, reaching nearly 90% after 30 h. Lactococcus, Pediococcus, Enterococcus, and Lactobacillus could adapt to the fermentation environment of tilapia surimi, and rapidly grow during the fermentation process. Lactococcus was the most important genus in fermented tilapia surimi, whose relative abundance increased significantly from 12.6% to 64.9% after 18 h, followed by Pediococcus with a relative abundance of 13.2% after 30 h fermentation. The quality evaluation showed that the gel strength, whiteness, hardness, and total plate count progressively increased with fermentation time, while the pH, adhesiveness, springiness, chewiness, and cohesiveness decreased when compared with those observed before fermentation. The correlation between core genera and quality indices was analyzed using Pearson correlation analysis and principal component analysis (PCA). As results, the increase in acid-producing bacteria such as Lactococcus, Pediococcus, Enterococcus, Enterobacter, and Citrobacter was positively correlated with the decrease in pH, as well as the improvement in the key quality indexes such as gel strength, whiteness, and hardness. These results showed that lactic acid bacteria such as Lactococcus, Pediococcus and Enterococcus, especially Lactococcus, played an important role in the quality formation of fermented tilapia surimi, which will provide an important theoretical basis for directional screening for functional microorganisms suitable for tilapia surimi fermentation and targeted improvement of the quality of fermented tilapia surimi.

Key words: fermented surimi; microbial community; tilapia; quality; high-throughput sequencing