Geographical origin traceability of muskmelon from Xinjiang province using stable isotopes and multi-elements with chemometrics

Abstract

Xinjiang muskmelon is a popular fruit in China that is exported worldwide. In particular, Hami muskmelon is classified as a protected geographical indication (PGI) product, and consequently it is more desirable and sells at a higher market price than products from other regions. Origin mislabeling and fraudulent substitution of Hami PGI muskmelon products by non-PGI products are frequently reported, which damages its reputation and market advantage. In this study, the geographical origin of muskmelon from Xinjiang was investigated using stable isotopes and multi-element analyses with chemometrics. Four stable isotopes (δ13C, δ15N, δ2H, δ18O) and seventeen elemental contents (Na, Al, P, K, Ca, Cr, Mn, Co, Ni, Cu, As, Sr, Mo, Cd, Sb, Ba, Pb) of 239 batches of muskmelon were collected from 13 administrative regions distributed across Xinjiang Province. One-way analysis of variance (ANOVA) was used to compare these regional differences using stable isotopes and multi-elements, and showed that a single variable could not fully classify all sample origins. A multivariate model was developed using linear discriminant analysis (LDA) based on stable isotope and multi-element data. The discriminant accuracies of 13 localities across Xinjiang Province was unsatisfactory with values as low as 46.2 % for Changji. Muskmelon from Kashi were misclassified as Aksu (20 %) and Bazhou (16.7 %) respectively. Further LDA modeling was undertaken after the 13 administrative regions were reduced to 6 geographical production regions from Xinjiang. Classification accuracies improved significantly; 100 % for Altay, 91.9 % for Hami and more than 79.1 % for other regions. Therefore, this strategy may be a useful and complementary tool to combat origin mislabeling of Hami PGI muskmelons from other Xinjiang regions, effectively ensuring food integrity and promoting origin certainty of PGI Hami muskmelon from Xinjiang.