**5. Conclusions**

Our comparative metabolomics analysis revealed distinctive metabolic profiles of the CBP relative to other bee pollen, including rose, apricot, lotus, rape, and wuweizi bee pollen. Among the differential compounds, L-Theanine and ECG were detected exclusively in all the CBP samples, and showed the highest discriminatory power. Further quantification based on targeted metabolomics demonstrated the content of L-theanine (819.45–2314.01 mg/kg) and ECG (90.95–430.70 mg/kg) in the CBP samples. The feasibility of easy detection and quantification of ECG and L-theanine in bee pollen demonstrates their possible practical application as marker compounds for CBP authentication.

**Supplementary Materials:** The following supporting information can be downloaded at: https:// www.mdpi.com/article/10.3390/foods12142661/s1, Table S1: Compounds identified in bee pollen samples. Table S2: Relative abundance of the identified compounds in bee pollen samples.

**Author Contributions:** D.Q.: conceptualization, formal analysis, writing—original draft. M.L.: formal analysis, writing—review and editing. J.L.: resources, supervision, validation, writing—review and editing. C.M.: project administration, formal analysis, writing—original draft. All authors have read and agreed to the published version of the manuscript.

**Funding:** The study was funded by the Agricultural Science and Technology Innovation Program in China (CAAS-ASTIP-2021-IAR) and the Earmarked Fund for Modern Agro-Industry Technology Research System in China (CARS-44).

**Data Availability Statement:** Data is contained within the article.

**Conflicts of Interest:** Author M.L. was employed by the company Agilent Technologies (China) Co. Ltd. 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.
