Correlation between microbial community, physicochemical properties, and characteristic flavor compounds of Yangjiang douchi

Highlights • Using HS-SPME-GC-MS, 33 key flavor compounds (OAV ≥ 1) were identified; • Spearman correlation analysis revealed that 6 bacterial and 9 fungal genera were core microbial genera; • Aspergillus spp. was the dominant genus in the pre-fermentation stage, and the post-fermentation was mainly Millerozyma spp.. • Aspergillus spp. promotes the generation of 1-octen-3-one, while Millerozyma spp. has a positive effect on many esters. Douchi is a fermented food, which has a unique flavor after natural fermentation. However, the correlation between the microbial community and volatile flavor compounds is poorly studied. This study used miseq sequencing and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) techniques to detect the dynamic changes of microbial succession and volatile compounds during fermented douchi and Spearman correlation analysis. The results revealed that a total of 33 key flavor compounds were identified, among which the esters contributing to fruity and floral aromas were the main ones. The dominant strains included Bacillus spp., Millerozyma spp., and Aspergillus spp.. Further analysis showed that in the post-fermentation stage, various yeast species were highly positively correlated with key flavor compounds such as 2-ethyl-methylbutanoate (fruity), phenylacetaldehyde (floral). Furthermore, Aspergillus spp. was a positive correlation with 1-octen-3-one (mushroom). This study provides new insights into the analysis of microbial community succession and characteristic flavor of Yangjiang douchi, which also offers valuable guidance for quality control and the subsequent screening of potential new starter cultures.