Abstract: A method for geographical origin discrimination of peach was established to provide technical support for the protection of geographical indication products and for tracing the geographical origin of agricultural products. Ninety-two samples of common peach cultivars were collected from four producing areas: the counties of Shunping, Laoting and Yongqing in Hebei Province and Pinggu district, Beijing in this study. The stable carbon, nitrogen, hydrogen and oxygen isotope ratios in peach were determined by elemental analysis-isotope ratio mass spectrometry. Inductively coupled plasma mass spectrometry was used to determine the contents of 16 rare earth elements. Multiple comparative analysis and general discriminant analysis were performed to establish a discriminant model for identifying the geographical origin of peach. Multiple comparative analysis showed that there were significant differences in nitrogen isotopes between Pinggu grown peach and those from other producing areas (P < 0.05); significant differences were found in carbon and oxygen isotope ratios between peaches grown in hilly regions (Pinggu and Shunping) and those grown in plain regions (Laoting and Yongqing) (P < 0.05), and the contents of the rare earth elements Ce, Eu, Gd and Er showed the most significant difference among different producing places (P < 0.05). According to the results of multiple comparative analysis, four stable isotopes (δ13C, δ15N, δ2H and δ18O) and eight rare earth elements (Y, Ce, Eu, Sm, Pr, Nd, Gd and Er) were selected for general discriminant analysis. Three discriminant functions with significant correlations were determined (P < 0.05). The overall correct discrimination rates for original peach samples from different geographical origins in back substitution and cross-validation test were 97.8% and 95.7%, respectively. Conclusively, stable isotope and rare earth element fingerprint analysis combined with chemometrics is feasible to identify the geographical origin of peach in small spatial scale.

Key words: peach, geographical origin traceability, stable isotopes, rare earth elements, discriminant analysis