## 3 Results and Discussion
### Conclusions  
Based on the above, this study investigated the formation of flavor compounds during the CFB fermentation process using GC-FID, HS-SPME-GC/MS, HPLC, and high-throughput sequencing. The results showed that _L. plantarum_ contributed greatly to the increase in acid content, while the increase in ester content was also associated with _P. anomala. L. plantarum_ accumulated precursors for ester production, while _P. anomala_ had a strong ester-producing ability. In addition, 68 volatile flavor compounds, including aldehydes, alcohols, hydrocarbons, esters, ketones, acids, and phenols, were identified by HS-SPME-GC/MS analysis. During the CFB fermentation process, the types (alcohols, esters, ketones, and hydrocarbons) and contents of volatile flavor compounds (phenylethylal alcohol, (E)-2-octenal, and diethyl succinate) increased significantly. This increase was closely related to _L. plantarum_ and _P. anomala_, which were able to enhance the contents of esters under the premise of increasing the alcohol content, proving that the addition of a mixture of _L. plantarum_ and _P. anomala_ was able to significantly increase the contents of flavor compounds. Therefore, this study offers valuable insights into the impact of _P. anomala_ and _L. plantarum_ on the CFB fermentation process, functioning as a reference for the optimization and advancement of CFB fermentation technologies. Future research will explore the changes in flavor precursor substances and the formation pathways of volatile flavor compounds in CFB, along with their application prospects. In conclusion, this study provides a pathway for the formation of increased volatile flavor compounds in CFB. The results of these studies provide for an in-depth understanding of the microbial community dynamics and the formation mechanisms of flavor compounds in the fermentation process of CFB. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/foods13213497/s1](https://www.mdpi.com/article/10.3390/foods13213497/s1)]([https://www.mdpi.com/article/10.3390/foods13213497/s1](https://www.mdpi.com/article/10.3390/foods13213497/s1)), Table S1: Orthogonal experimental design of _Pichia anomala_; Table S2: Orthogonal experimental design of _Lactobacillus plantarum_; Table S3: Orthogonal experimental design of mixed strains; Table S4: The variation in the contents of flavor substances in the fermentation process; Figure S1: The fermentation process of CFB; Figure S2: Changes in total organic acid content during CFB fermentation; Figure S3: Plots of principal component analysis and OPLS-DA model correlation analysis for volatile flavor substances; Figure S4: The chromatograms for analysis of standards and real samples. **Author Contributions:** Conceptualization, W.Z., J.L., W.B. and S.H. ; Methodology, P.F., Y.F., W.Z., J.L., W.B. and S.H. ; Software, P.F., X.L. and Y.F. ; Validation, W.Z., J.L. and W.B. ; Formal analysis, P.F. and Y.F. ; Investigation, P.F., X.L., Y.F. and S.H. ; Resources, X.L. ; Writing--original draft, P.F. and Y.F. ; Writing--review & editing, P.F., X.L., Y.F. and J.L. ; Supervision, W.Z. and W.B. ; Project administration, W.Z. and W.B. ; Funding acquisition, W.Z. and W.B. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by Guangzhou Basic and Applied Basic Research Project (SL2023A04J1441), Key-Area Research and Development Program of Guangdong Province (2020B020226008), The Research Capacity Enhancement Project of Key Discipline in Guangdong Province (2021 ZDJS005), Project of Science and Technology Correspondent Team Stationed in Town to Help Town and Village (Yueke Hanong Zi [2021] No. 1056) and Key construction discipline research ability enhancement project of Guangdong Province (2022 ZDJS022). **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable.