Development of a Method for Determination of the Geographic Origin of Taros Using Fluorescence Fingerprint

Abstract

Fluorescence fingerprints (FF) of 137 Japanese taro samples and 23 Chinese ones, harvested in 2008, were measured in the excitation and emission wavelengths ranging from 200 to 900 nm at 10 nm intervals after grinding and homogenization. The obtained data set was split into calibration and validation data sets. Canonical discriminant analysis was applied to the former to develop a model for the prediction of the country of origin from its FF. Then the model was applied to the validation set to test the model accuracy, which resulted in the misclassification rate of 9.4%. The area under the curve (AUC) of the receiver operating characteristics for the FF method was equivalent to those for inorganic elements composition and the combination of inorganic elements composition and the Sr isotopic ratio. These results showed the potential of FF as a quick and accurate method to determine the geographic origin of taros.