## 4 Conclusions  
This study evaluated the correlations between the microbiota and flavor compounds of seven different douchis. Among them, _Bacillus_, _Pseudomonas_, _Tetragonococcus_, and _Weissella_ were the predominant bacteria, while _Aspergillus_, _Mucor_, _Pencillium_, and _Trichothecium_ were the major fungi. As for amino acids, the content of Glu was the most prevalent, followed by Asp and Cys. Bitter-causing amino acids had the highest concentrations, which was consistent with the result after sensory tasting. As for the volatile components, 100 volatile compounds were spotted in total. Despite having few volatile components in common, all the douchi appear to have fruity, caramel, floral, and cocoa aromas.  
The research was successful in developing a novel correlation model to visualize the complex relationship among the amino acids, volatile components, and microorganisms. Glu had negative correlations with lots of microorganisms. 3-Methyl-1-butanol, phenylethyll alcohol, 1-octen-3-ol, ethyl isobutyrate, and isoamyl acetate had positive correlations with _Mucor_ and _Penicillium_ and were negatively correlated with _Hyphopichia_, _Meyerozyma_, and _Issatchenkia_.  
The present study will establish a solid foundation for the further validation of correlations between microorganisms and flavor while also enhancing the microbial spectrum information pertaining to douchis from different corporations. These findings serve as a fundamental basis for selecting the optimal flavor-producing strain for douchi production.  
The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/foods14050810/s1](https://www.mdpi.com/article/10.3390/foods14050810/s1)]([https://www.mdpi.com/article/10.3390/foods14050810/s1](https://www.mdpi.com/article/10.3390/foods14050810/s1)), Table S1: The contents of the amino acids in the douchi samples; Table S2: The contents of the volatile components between the douchi products.  
Conceptualization, D.T. and L.Y.; methodology, J.K., Q.L. and M.D.; software, J.K. and Q.L.; validation, M.L. and M.D.; formal analysis, D.T., W.L., C.B. and L.Y.; investigation, J.K. and Q.L.; resources, D.T. and J.M.; data curation, M.D. and M.L.; writing--original draft preparation, D.T. and J.K.; writing--review and editing, M.B., C.B., W.L. and L.Y.; supervision, M.L. and L.Y.; project administration, L.Y. and J.M.; funding acquisition, D.T. and W.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Natural Science Foundation at Chongqing Technology and Business University (2256017) and the Natural Science Foundation of Chongqing (Grant No. CSTB2022 NSCQ-LZX0078).  
Not applicable.  
The original contributions presented in this study are included in the article/Supplementary Materials; further inquiries can be directed to the corresponding author.  
Author [PERSON], [PERSON], [PERSON] and [PERSON] was employed by the company Chongqing Wanbiao Testing Technology Ltd. They participated in explori ng the core functional microbiota related with flavor compounds in douchi from Sichuan-Chongqing region in the study. The role of the company was major participating team. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.