Authenticating the origin of Pakchoi using metal content in the edible part of Pakchoi at Hanoi market, Vietnam

Pakchoi (Brassica rapa subsp. chinensis) is a familiar vegetable and is widely grown in Vietnam and many other Southeast Asian countries. Like other Brassica plants, Pakchoi has long been known for its ability to accumulate a variety of metals. Using the metal content data in the edible part of Pakchoi from Chuong My, Me Linh, and Dan Phuong (3 areas specializing in growing Pakchoi serving Hanoi market) during the period from September 2021 to April 2024, this study evaluated the ability to authenticate the origin of Pakchoi using the PCA and LDA methods. 27 kinds of metal in the edible parts of Pakchoi from these areas, including Li, Bo, Mg, Al, Ti, V, Cr, Mn, Zn, Fe, Co, Ni, Cu, As, Rb, Sr, Nb, Mo, Ag, Cd, Sb, Cs, Ba, Hg, Tl, Pb, and Bi, were determined by ICP-MS. Multivariate Statistical Analysis methods (Principal component analysis-PCA and Linear Discriminant Analysis-LDA) were used and LDA method was successful in distinguishing the three geographical areas. Of the total 27 metals, the characteristic metals used for distinction in LDA were shown, including: As, Ba, Co, Cs, Li. In addition, the model constructed by LDA showed the ability to accurately recognize 27/27 prepared prediction samples. This research shows the potential of using metal content results in building a model to authenticate the geographical origin of Pakchoi in particular and other vegetable crops in general in the food market in the Hanoi, Vietnam.