Determination of the geographic origin of brown-rice with trace-element composition

The distinction of the geographic origin of bro cvn-rice samples by their trace-element composition was studied. Thirty four kinds of unhulled rice samples (Oryza sativa L. cv. Koshihikari, produced in 1996), including those fertilized in different ways at the same place, were collected from 27 different locations. After hulling, about 1 g of brown-rice (about 50 grains without pulverization) were digested with nitric and perchloric acid. P, K, Mg, Ca, Mn, Zn, Fe and Cu were determined by ICP-AES; Rb, Mo, Ba, Sr, Ni, Cd, Cs, Pb, Al, Cr and Co were determined by ICP-HRMS. Using the analytical results of 13 elements (P, K, Mg, Ca, Mn, Zn, Fe, Cu, Rb, Mo, Ba, Sr, Ni), brown-rice samples were analyzed using chemometrics software, including cluster analysis and principal component analysis (PCA), to categorized into particular groups. As a result, cluster analysis (Ward method) and PCA using 9 elements (Mn, Zn, Fe, Cu, Rb, Mo, Ba, Sr, Ni) could distinguish rice samples cultivated in the Tohoku/Kanto area from those in Hokuriku, and those in Tohoku from those in Kanto.