Metabolome analysis to investigate the effect of controlled fermentation on taste-related metabolites in terasi.

Introduction: Terasi is a fermented shrimp paste unique to Indonesia and is used in dishes to add umami and saltiness. In a previous study, the controlled fermentation of terasi was optimized using starters containing three bacterial isolates: Staphylococcus saprophyticus, Bacillus subtilis, and Lactobacillus murinus. However, the influence of controlled fermentation using these starters on the metabolites in terasi has not yet been studied.

Objectives: Therefore, this study aimed to investigate the effect of controlled fermentation on taste-related metabolites in terasi using a metabolomics approach.

Results: Non-targeted analysis indicated that amino acids contributed to variations during fermentation. Subsequently, targeted analysis of amino acids revealed that terasi subjected to controlled fermentation using a starter with a 2:1:2 ratio of S. saprophyticus, B. subtilis, and L. murinus, respectively, resulted in a product containing D-amino acids, such as D-Asp, D-Gln, and D-Leu that was unique when compared to other terasi products prepared using controlled fermentation. Genetic analysis of isolates from the terasi produced using controlled fermentation was also carried out, and this is the first study to suggest that Staphylococcus spp. has the potential to produce D-amino acids.

Conclusion: In conclusion, the ratio of bacterial species in starter cultures used in controlled fermentation influenced the amino acid profile of the product and starters with a higher ratio of Staphylococcus spp. may result in the production of D-amino acids.