Abstract
Sour shrimp paste (SSP) is a traditional fermented food produced by co-fermenting shrimp and grains. It is characterized by a unique sour and fruity aroma that contrasts with the fishy notes of conventional shrimp paste (CSP). GC-MS analysis revealed that SSP contains significantly higher levels of esters (656.50-4717.62 mg/kg) and alcohols (98.30-538.11 mg/kg), which are 2-10 times higher than in CSP. CSP has more heterocyclic compounds. SSP was notably enriched in branched-chain esters, ethyl butanoate, and phenyl esters, many of which are derived from amino acid metabolism. Microbial profiling indicated higher abundances of Wallemia, lactic acid bacteria, and yeasts in SSP. Correlation analysis further identified Ligilobacillus, Vagococcus, Peptoniphilus, Metschnikowia, Wallemia, and Saccharomyces as key microbiota strongly associated with esters, alcohols, and acids. These results systematically clarify the biochemical and microbial basis underlying the unique sensory qualities of SSP.