title: Precursors of 2-acetyl-1-pyrroline, a potent flavor compound of an aromatic rice variety.
abstract: The biological formation of a potent flavor compound, 2-acetyl-1-pyrroline, in the aromatic rice variety (Khao Dawk Mali 105) was studied in seedlings and callus of the rice. Concentrations of 2-acetyl-1-pyrroline were determined by GC-MS-SIM using an isotope dilution method. Increases in concentration occurred when proline, ornithine, and glutamate were present in solution, with proline increasing the concentration by more than 3-fold compared to that of the control. Results of tracer experiments using (15)N-proline, (15)N-glycine, and proline-1-(13)C indicated that the nitrogen source of 2-acetyl-1-pyrroline was proline, whereas the carbon source of the acetyl group was not the carboxyl group of proline. 2-acetyl-1-pyrroline was formed in the aromatic rice at temperatures below that of thermal generation in bread baking, and formed in the aerial part of aromatic rice from proline as the nitrogen precursor.
authors.affiliation: Food Science and Technology Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan. tadashi@jircas.affrc.go.jp
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yoshihashi
authors.forename: Nguyen Thi Thu
authors.initials: NT
authors.lastname: Huong
authors.forename: Hideo
authors.initials: H
authors.lastname: Inatomi
mesh_terms: D002247:Carbon Isotopes; D003903:Deuterium; D008401:Gas Chromatography-Mass Spectrometry; D018698:Glutamic Acid / Q000494:pharmacology; D007201:Indicator Dilution Techniques; D009587:Nitrogen Isotopes; D009952:Ornithine / Q000494:pharmacology; D012275:Oryza / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D018514:Plant Structures / Q000737:chemistry; D011392:Proline / Q000494:pharmacology; D011758:Pyrroles / Q000032:analysis*; D013649:Taste
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D011758:Pyrroles; D018698:Glutamic Acid; D011392:Proline; D003903:Deuterium; D009952:Ornithine; C426303:2-acetyl-1-pyrroline