Accurate geographical origin identification of winter jujube PGIs by mineral elements and stable isotopes in flesh and pit

Geographical mislabeling of PGI winter jujube undermines product integrity. Here, we analyzed 29 elements and six stable isotopes in flesh and pit of 206 samples from four PGIs. Significant compositional differences were found among four PGIs (p < 0.05). Key markers (Sb, Mo, Cd, Y, δ¹⁸O_f, δ²H_f, Se, La, δ¹³C_p, Cr, Th, U, and Br) were identified via OPLS-DA (VIP > 1) and LDA incorporating effect size (η²) analysis. Integrating comprehensive stable isotope and element data from pits and flesh, the full-feature-fusion LDA model achieved 92.7% accuracy and demonstrated robustness in inter-annual validation (training set: 97.4%; test set: 95.6%). This confirms that tissue elemental and isotopic fingerprints combined with LDA provide reliable PGI winter jujube authentication.