title: [Structural analyses of unknown red dyes detected in dried strawberry].
abstract: We examined two unknown red dyes (designated as red dyes "A" and "B") from a dried strawberry package with a label that indicated the presence of food red No. 40 (R40). Red dye "A" was identified as trisodium 3-hydroxy-4-[(2'-methoxy-5'-methyl-4'-sulfonatophenyl)azo]-2,7-naphthalenedisulfonate (CSA-R) by HPLC, UV-VIS spectra and MS spectra. This compound is one of the four reported subsidiary colors of R40. Detailed analyses of red dye "B" by MS and NMR demonstrated that its structure was disodium 3-hydroxy-4-[(2'-methoxy-5'-methyl-4'-sulfonatophenyl)azo]-2-naphthalenesulfonate. Red dye "B" is a structural isomer of R40, that has not been reported previously. Our results suggest that the two minor red dyes were subsidiary colors contained in R40, which had been added to the dried strawberries.
authors.affiliation: Tokyo Metropolitan Institute of Public Health, Tokyo, Japan. Tetsuya_Shindou@member.metro.tokyo.jp
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Shindo
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sadamasu
authors.forename: Keiko
authors.initials: K
authors.lastname: Suzuki
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Akiko
authors.initials: A
authors.lastname: Togawa
authors.forename: Junichi
authors.initials: J
authors.lastname: Nakajima
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Nakazato
authors.forename: Yoko
authors.initials: Y
authors.lastname: Uematsu
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D005505:Food Coloring Agents / Q000737:chemistry*; D057141:Food, Preserved; D031985:Fragaria / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry
chemical_list: D005505:Food Coloring Agents