title: Geographical origin of polished rice based on multiple element and stable isotope analyses.
abstract: We determined carbon and nitrogen contents (C and N contents) and stable carbon, nitrogen, and oxygen isotopic compositions (δ(13)C, δ(15)N, and δ(18)O) of polished rice in order to develop a simple method to discriminate its geographical origin. As a first attempt, we examined a single cultivar, Koshihikari rice, from 14 different cultivation areas including Australia (n=1), Japan (n=12), and USA (n=1). For all rice samples, C and N contents and the isotopic compositions are consistent with those of general plant materials, being 37.2-40.0% (C content), 0.8-1.4% (N content), -27.1 to -25.4% (δ(13)C), +0.4 to +9.0% (δ(15)N), and +18.8 to +22.9% (δ(18)O). However, its cultivated area is clearly distinguished by a pentagonal radar plot based on the elemental and isotopic compositions. Thus, the comparison of C and N contents and δ(13)C, δ(15)N, and δ(18)O values would potentially be useful for rapid and routine discrimination of geographical origin of the polished rice.
authors.affiliation: Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0397, Japan. Electronic address: suzuki-yaeko@ed.tmu.ac.jp.
authors.forename: Yaeko
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, 2-15 Natushima-Cho, Yokosuka 237-0061, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Chikaraishi
authors.affiliation: Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, 2-15 Natushima-Cho, Yokosuka 237-0061, Japan.
authors.forename: Nanako O
authors.initials: NO
authors.lastname: Ogawa
authors.affiliation: Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, 2-15 Natushima-Cho, Yokosuka 237-0061, Japan.
authors.forename: Naohiko
authors.initials: N
authors.lastname: Ohkouchi
authors.affiliation: Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Korenaga
keywords: C and N contents; Geographical origin; Koshihikari; Rice; δ(13)C; δ(15)N; δ(18)O