Discrimination of Geographical Origin of Asian Garlic Using Isotopic and Chemical Datasets under Stepwise Principal Component Analysis |
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Authors: | Tsang‐Sen Liu PhD Jhen‐Nan Lin MS Tsung‐Ren Peng PhD |
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Institution: | 1. Agricultural Chemistry Division, Taiwan Agricultural Research Institute, Taichung, Taiwan;2. Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung, Taiwan |
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Abstract: | Isotopic compositions of δ2H, δ18O, δ13C, and δ15N and concentrations of 22 trace elements from garlic samples were analyzed and processed with stepwise principal component analysis (PCA) to discriminate garlic's country of origin among Asian regions including South Korea, Vietnam, Taiwan, and China. Results indicate that there is no single trace‐element concentration or isotopic composition that can accomplish the study's purpose and the stepwise PCA approach proposed does allow for discrimination between countries on a regional basis. Sequentially, Step‐1 PCA distinguishes garlic's country of origin among Taiwanese, South Korean, and Vietnamese samples; Step‐2 PCA discriminates Chinese garlic from South Korean garlic; and Step‐3 and Step‐4 PCA, Chinese garlic from Vietnamese garlic. In model tests, countries of origin of all audit samples were correctly discriminated by stepwise PCA. Consequently, this study demonstrates that stepwise PCA as applied is a simple and effective approach to discriminating country of origin among Asian garlics. |
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Keywords: | forensic science discrimination of country of origin for garlic trace elements stable isotopes principal component analysis (PCA) discrimination model test |
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