Geographical identification of Oryza sativa “MR 220CL” from Peninsular Malaysia using elemental and isotopic profiling

Indication of rice geographical origin is important in preventing food fraud issues and meets the consumers’ expectation for acquiring high quality food. This study examined the elemental and stable isotope compositions of rice samples from MR 220CL cultivar in order to distinguish the geographical origin. A total of 53 rice samples from Kedah (n = 27), Selangor (n = 20) and Langkawi (n = 6) were analyzed for elemental and stable isotope compositions. The instrumental neutron activation analysis was applied to determine the elemental concentrations of aluminum (Al), arsenic (As), bromine (Br), chlorine (Cl), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), rubidium (Rb) and zinc (Zn) whilst the stable isotopes of δ13Carbon (δ13C) and δ15Nitrogen (δ15N) were analyzed using isotope ratio mass spectrometry. The results showed that the concentrations of Al, As, Br, Cl, K, Mg, Na, Rb, Zn and isotopic values of δ13C and δ15N of the rice samples were significantly different (p < 0.05) between the three regions. The rice cultivar was classified into these regions using chemometrics approach of principle component analysis and linear discriminant analysis that achieved high accuracy of 98.1% correct classification. Rubidium and δ15N were shown as the effective indicators for rice from Langkawi, δ13C for rice from Kedah and As, Br, Cl, K, Mg, Na and Zn were the reliable markers for rice from Selangor. The internal and external validation tests of classification model also demonstrated satisfactory prediction accuracy of 96.2% and 84.6%, respectively. Therefore, the elemental compositions and stable isotopes have high potential to be utilized in authenticating the rice cultivar from different origins.