Verifying the provenance of rice using stable isotope ratio and multi-element analyses: a feasibility study

Different varieties of rice grown in various countries around the world (Australia, China P.R., France, India, Italy, Japan, Korea, Malaysia, Myanmar, Pakistan, Spain, Taiwan, Thailand, USA and Vietnam) were analysed using isotope ratio mass spectrometry and inductively coupled plasma mass spectrometry. The stable isotope ratios of carbon, nitrogen, oxygen and hydrogen and the multi-elemental compositions were assessed as variables for discrimination of the geographical origins of the rice samples. The data were processed by canonical discriminant analysis (CDA) enabling classification according to geographical origin. Fifteen key variables were identified by CDA as providing the maximum discrimination between the rice samples across different rice types and categorised on the basis of broad geographical areas (Asia, Australia, Europe, India and Pakistan, North America and Southeast Asia), enabling 90.7% correct classification for the model generated. This feasibility study demonstrated that the methodology has good potential in identifying the geographical origin for different rice types and useful as a database for the examination of unknown rice samples.