Elucidating the impact of salt concentration on volatile flavor profiles and microbial dynamics in fermented cockle paste using GC-IMS and high-throughput 16S rDNA sequencing

In the present study, cockles were utilized as the raw material to investigate how different salt concentrations and fermentation periods influence the physicochemical indices, microbial community shifts, and volatile flavor components of cockle paste. Through the analysis of volatile flavor substances via GC-IMS, a total of 77 volatile flavor compounds were identified, among which aldehydes accounted for the largest proportion. High-throughput 16S rDNA sequencing was applied to decode the composition of dominant microbiota in the cockle paste samples. At the phylum level, the key microbial communities in cockle paste included Proteobacteria, Verrucomicrobiota, and Actinobacteriota; at the genus level, Psychrilyobacter became the dominant genus. Moreover, this study analyzed the correlations between dominant microbial communities and volatile components. By means of VIP value analysis, it was found that there was a significant correlation between the top 20 dominant microbial species and flavor components. Notably, Psychrilyobacter showed a positive correlation with 11 volatile flavor components, and these components together formed the characteristic flavor of naturally fermented cockle paste. The fermentation process proposed in this study offers a new method for the value-added utilization of low-value shellfish resources.