Flavor Metabolic Pathways of Fermented Large Yellow Croaker with Pediococcus pentosaceus

In this study, low-salt fermented large yellow croaker was prepared by inoculating low-salt cured yellow croaker with Pediococcus pentosaceus and fermenting it, its flavor profile and volatile flavor compounds were characterized using flavor metabolomics and molecular sensory science, and its key odor-active compounds were identified. The differential metabolism of fatty acid flavor precursors was investigated and the correlation between the key odor-active compounds and free fatty acids was analyzed. Moreover, the metabolic pathways of P. pentosaceus for promoting the production of the key odor-active compounds from fatty acids were explored. The results showed that fermentation with P. pentosaceus reduced the grassy and fishy smell while enhancing the fatty and meaty aroma, thereby improving the acceptability of large yellow croaker. Eight compounds, including heptanal, 1-octen-3-ol, nonanal, (E,Z)-2,6-nonadienal, (E)-2-nonenal, decanal, undecanal, and (E,E)-2,4-decadienal, were identified as the key odor-active compounds. The study also elucidated the potential metabolic pathways for the oxidation and degradation of four differential fatty acids, including (Z,Z)-9,12-octadecadienoic acid and (Z,Z,Z)-9,12,15-octadecatrienoic acid, by P. pentosaceus to produce the key odor-active compounds 1-octen-3-ol, (E,Z)-2,6-nonadienal, (E)-2-nonenal, decanal, and (E,E)-2,4-decadienal.