Discrimination of the geographical origin of dry red pepper using inorganic elements: A multielement fingerprinting analysis

This study was based on inductively coupled plasma optical emission spectroscopy and mass spectrometry. The purpose of this study was to develop an accurate method for clearly discriminating the origin of dry red pepper. Sixty-four domestic and 51 imported samples were acid treated in a microwave system. The geographical origin of each sample was identified using the contents of 60 elements. The OPLS-DA results showed that the R2 and Q2 values were 0.873 and 0.765, respectively, indicating a high ratio and prediction ratio of this model. A total of 26 elements with a VIP (Variable Importance in Projection) value of greater than 1 were selected, and each element had a decisive influence on the domestic and imported groups. An ROC (Receiver Operating Characteristic) analysis confirmed the accuracy of the identification of domestic and imported products using the selected 26 elements. The accuracy based on the ROC was 98.7%. A heatmap was used to select elements that were influential in identifying domestic and imported dry red pepper samples. All of the most influential elements were rare earth elements (REEs). The REE content of dry red pepper was significantly higher in imported than in domestic samples. CDA (Canonical Discriminant Analysis) showed that the accuracy of classification by group was 100% for each group. •This is the first paper to rare earth elements for dry red pepper.•The perform geographical origin discrimination based on rare earth elements.•ICP analytical method is developed for determining geographical origin.•The ROC model accuracy for dry red pepper is 98.7%, and the CDA accuracy is 100%.