title: Analysis of (all-E)-lutein and its (Z)-isomers during illumination in a model system.
abstract: Light induced-isomerization of (all-E)-lutein in organic solvent and starch model systems was investigated. Lutein and its (Z)-isomers were separated by HPLC using a C30 column and gradient mobile phase based on methanol-methyl-tert-butyl ether-water in 24min. (All-E)-lutein and twelve (Z)-isomers of lutein, in addition a small amount of (all-E)-zeaxanthin and (9Z, 9'Z)-zeaxanthin were identified by HPLC-DAD-APCI-MS. Five di-(Z)-luteins were identified for the first time, namely, (9Z, 9'Z)-, (9Z, 13Z)/(9 Z, 13'Z)-, (13Z, 15Z)- and (9Z, 15Z)-lutein and (9Z, 9'Z)-zeaxanthin. A mixture of (9Z)-lutein and of (9'Z)-lutein was the main product of the iodine-catalyzed photo-isomerization. (9Z, 13Z)/(9Z, 13'Z)-lutein were the major di-(Z)-isomers of lutein formed. The susceptibility of lutein to degradation was much less under dark storage than under lighted storage in starch model system. Isomerization and degradation of lutein and its (Z)-isomers proceeded simultaneously in all the model systems.
authors.affiliation: Institute of Farm Product Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; College of Forestry, Northeast Forestry University, Harbin 150040, China. Electronic address: lidajing@163.com.
authors.forename: Dajing
authors.initials: D
authors.lastname: Li
authors.affiliation: Institute of Farm Product Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: xyd15838746910@163.com.
authors.forename: Yadong
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: Institute of Farm Product Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China. Electronic address: zzyszy2012@163.com.
authors.forename: Zhongyuan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Institute of Farm Product Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China. Electronic address: liuchunquan2009@163.com.
authors.forename: Chunquan
authors.initials: C
authors.lastname: Liu
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D007536:Isomerism; D008027:Light; D014975:Lutein / Q000032:analysis* / Q000737:chemistry / Q000528:radiation effects*; D013058:Mass Spectrometry / Q000379:methods; D010782:Photolysis; D012997:Solvents / Q000737:chemistry; D013213:Starch / Q000737:chemistry; D013997:Time Factors
chemical_list: D012997:Solvents; D013213:Starch; D014975:Lutein
keywords: (All-E)-lutein; Degradation; Isomerization; Light; Model