Study on Origin Tracing of Dried Tangerine Peel Using Mineral Element Fingerprints

By analyzing the differences of mineral element contents in dried tangerine peel from different producing areas, combined with multivariate statistical analysis, the effective origin traceability indexes based on mineral element fingerprint analysis technology were selected to construct its discrimination model of different origin identification. In this study, 206 dried tangerine peel samples were collected from three different producing areas as Guangdong, Fujian and Chongqing. The contents of 32 mineral elements were determined by inductively coupled plasma mass spectrometer (ICP-MS) and inductively coupled plasma atomic emission spectrometer (ICP-AES). Combined with analysis of variance, principal component analysis, linear discriminant analysis and orthogonal partial least squares discriminant analysis, a discriminant model of dried tangerine peel producing area was established. The results showed that 26 of the 32 mineral elements in the dried tangerine peel samples had significant differences between Guangdong and other two producing areas, and 11 of them had significant differences between the three different regions. After principal component analysis, four principal components could be extracted from the 32 mineral elements, representing 70.0% of the total index. Based on the principal component analysis, the dried tangerine peel samples could be preliminarily clustered according to their different origin. The main variables of the first two principal components were Dy, Sm, Gd, Pr, Nd, Y, La, Fe, Be, V, Ce, Sc, Co, P, Mo, As, Pb and B. Through linear discriminant analysis, 21 mineral elements K, P, Ca, Co, Cu, Mn, Mo, V, Ni, B, Li, Pb, As, Sr, Ti, Th, Gd, Sc, Nd, Pr and Y were determined as effective traceability indexes of the dried tangerine peel. Additionally, based on the discriminant model established by orthogonal partial least squares discriminant analysis, the importance of 13 elements Sc, B, Y, Co, Nd, La, Pr, Be, Gd, Dy, Sm, Mo and Fe were determined. For the discrimination models established by the two above-mentioned discrimination analysis methods, their overall correct discrimination rates of cross validation and external sample validation were both 100%, which basically achieved the origin discrimination of dried tangerine peel. The research suggested that the mineral element fingerprint analysis technology can be used for the origin traceability discrimination of dried tangerine peel.