Classification of Crab-Field Rice and Conventional Rice Based on Multi-Element, Stable Isotope, and Non-Targeted Metabolome Combined with Chemometrics

The quality of rice is closely related to its planting mode. The rice produced in rice-crab co-cultivation fields often enjoy higher prices and consumption enthusiasm than traditional rice due to the use of fewer chemical inputs, making it a key target of commercial fraud. In this study, multi-element, stable isotope, metabolite analysis techniques were synergistically applied with chemometric methods to distinguish between crab-field rice and common rice. Seven elements (Se, Rb, Cu, Cd, Ag, V, and Zn), two stable isotopes (<i>δ</i>¹⁵N and <i>δ</i>¹³C), and nine metabolites were identified as the most important discriminant variables. The discriminant analysis model based on seven elements and two stable isotopes, or based on nine metabolites, can completely distinguish between crab-field rice and conventional rice. The isotope, elemental, and metabolic fingerprint spectra selected in this study provide effective support for the authenticity identification of crab-field rice.