摘要
•C, N, O, H, S isotopes were used to determine garlic origin.•H, S and N isotopes were most useful for origin discrimination.•Pair-wise PLS-DA model was an appropriate discrimination method.•PGI Jinxiang garlic could be distinguished from other origins.
Jinxiang garlic is a well-known commodity with protected geographical indication (PGI) status in China and is also registered PGI in the European Union. A stable isotope profile (13C, 15N, 2H, 18O, and 34S) was used to construct a discrimination model to differentiate PGI Jinxiang garlic from other major garlic export countries (Argentina and Southeast Asian countries; Thailand and Vietnam), as well as garlic produced in other Chinese provinces (Guizhou and Hainan). Results showed that there were no significant isotope differences for Jinxiang garlic sampled from 13 towns across the county, especially for δ15N and δ2H. δ18O value was not a suitable classification variable for origin, but δ2H, δ15N, and δ34S values were found to be useful to characterize garlic origin. Chemometrics showed pair-wise partial least squares discriminant analysis (PLS-DA) model was an appropriate method to distinguish Jinxiang garlic from other locations, with a total discriminant accuracy of more than 89.5 % and 100% classification of PGI Jinxiang garlic. This study has potential to provide a suitable traceability method to authenticate Jinxiang garlic with PGI status in international markets.