<![CDATA[Rice (Oryza sativa L.) is a staple food for more than half of the global population and is available in various types, including white, red, black, brown, and basmati rice. Authentication of rice varieties and cultivation systems is increasingly important for ensuring food quality and preventing fraud. This study aimed to characterize the stable isotope composition of different rice types and to evaluate isotopic differences between organic and conventional cultivation systems using Elemental Analyzer–Isotope Ratio Mass Spectrometry (EA–IRMS). Carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios were measured in seven rice samples. The results showed that δ¹³C values ranged from −30.33‰ to −28.06‰, confirming that all samples belong to the C₃ photosynthetic group, while δ¹⁵N values ranged from 4.29‰ to 6.05‰, reflecting variability in nitrogen sources and soil processes. Each rice type exhibited a distinct isotopic profile, indicating the potential of isotope ratios as fingerprints for varietal differentiation. However, isotopic differences between organic and conventional samples were not consistently distinguishable due to overlapping values. These findings suggest that stable isotope analysis has potential as a tool for rice authentication in the Indonesian market. Nevertheless, the limited sample size in this study indicates that the results should be considered preliminary, and further validation using larger datasets and multivariate statistical approaches is required to improve classification accuracy.]]>
