Screening of flavor-presenting lactic acid bacteria from naturally fermented seafoods

In this study, ten high protease-producing isolates were selected from a total of 163 isolates obtained through the isolation and purification of fish sauce, shrimp paste, eel paste, and Dai Shan pickled fish. A total of 6 isolates were subjected to screening based on their bacteriostatic and acid-producing capabilities. Finally, two excellent strains of Lactiplantibacillus plantarum DZ3-1 and Companilactobacillus alimentarius DZ3-6, which significantly improved the flavor of fermented seafood, were screened by branched-chain aminotransferase activity, nicotinamide adenine dinucleotide-Glutamate dehydrogenase activity, optimal growth conditions, and fish isolated soluble protein (FISP) fermentation experiment. The results showed that L. plantarum DZ3-1 and C. alimentarius DZ3-6 had higher flavor enzyme activity. Both DZ3-1 and DZ3-6 have 2 flavor compounds (1-Penten-3-one and 3-methyl-Butanoic acid) with OAV values > 1, suggesting that these compounds contributed significantly to the overall flavor of the fermented FISP. 3-methyl-Butanoic acid was identified in all samples except the fermentation DZ3-7 group. It may be a flavor compound produced by the metabolism of branched-chain amino acids by 2 flavor enzymes.