Isotope Ratio Mass Spectrometry (IRMS)-Based Authentication of the Geographic Origins of (Bull.) Singer.

The growing consumption of has heightened concerns regarding its geographical authenticity. This study analyzed the proteins, 16 common amino acids, and 10 mineral elements (Ca, Cu, Fe, K, Mn, Mg, Na, Se, Sr, Zn) in samples from Fujian, Guangdong, Hubei, Jiangsu, Jiangxi, Shanghai, and Zhejiang, China, along with regional variations in stable isotope ratios. PCA and PLS-DA were applied for origin authentication. The results showed an average protein content of approximately 30 g/100 g (dry basis), with Guangdong samples being the highest. Amino acids exhibited significant regional differences, but the total essential amino acid and total amino acid contents did not. Mineral elements varied significantly by region, except for Cu and K. The Fujian, Hubei, Jiangxi, and Zhejiang samples exhibited significantly higher C and N values, while Shanghai samples had significantly higher H and O values. These differences enabled PCA to classify the samples into two groups: FHJZ (Fujian, Hubei, Jiangxi, Zhejiang) and GJS (Guangdong, Jiangsu, Shanghai). The PLS-DA model achieved 93.60% accuracy in distinguishing these two groups. Pairwise accuracy within the GJS group exceeded 80%, whereas that within the FHJZ group requires further improvement. These findings support the feasibility of stable isotope analysis for authenticating the geographical origin of .