Elucidating the mechanism underlying volatile and non-volatile compound development related to microbial amino acid metabolism during golden pomfret (Trachinotus ovatus) fermentation

Golden pomfret (Trachinotus ovatus) is an important farmed fish in Asia, often consumed following salting and natural microbial fermentation. Flavor development in fermented foods depends on the metabolism of fermenting microbes, especially amino acid metabolism. However, the microbes involved in golden pomfret fermentation and the mechanism by which they regulate flavor development are largely unknown. Accordingly, in this study, we investigated the microbial community and volatile and non-volatile compounds during the traditional fermentation of golden pomfret, focusing on amino acid metabolism. Thirty-five volatile compounds were detected. Glutamate, alanine, and leucine were the main amino acids responsible for the development of the characteristic taste of fermented golden pomfret. Metagenomic analyses were performed, and microbial genes for amino acid metabolism were functionally annotated, revealing the underlying mechanisms of flavor development during fish fermentation. Halobacterium, Clostridium, Natrinema, Alkalibacillus, Natrialba, and Vibrio were the dominant microbial genera with a major contribution to amino acid metabolism during fermentation and were strongly correlated with the majority of volatile compounds. The study provides a theoretical reference for the mechanism of flavor formation and important information on the microbial sources of volatile compounds derived from amino acids.