Unraveling the distinctive features of sour shrimp paste: A comparative analysis with conventional shrimp paste based on aroma and microbiota profiles

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. • Sour shrimp paste (SSP) possesses a unique aroma profile dominated by intense fruity and sour notes, distinct from conventional shrimp paste (CSP). • SSP contains key volatile compounds, notably esters, alcohols, and acids, at concentrations up to 10-fold higher than CSP. • SSP exhibits a microbial community highly enriched with lactic acid bacteria and yeasts. • SSP demonstrates a remarkably higher fungal abundance.