title: Analysis of palmitoyl apo-astaxanthinals, apo-astaxanthinones, and their epoxides by UHPLC-PDA-ESI-MS.
abstract: Food products enriched with fatty acid-esterified xanthophylls may result in deviating dietary apo-carotenoids. Therefore, free astaxanthin and its mono- and dipalmitate esters were subjected to two degradation processes in a methanolic model system: light-accelerated autoxidation and hypochlorous acid/hypochlorite (HOCl/OCl(-)) bleaching. Reversed phase ultrahigh-performance liquid chromatography photodiode array with in-line electrospray ionization mass spectrometry (RP-UHPLC-PDA-ESI-MS) was used for assessment of degradation products. Apo-astaxanthinals and -astaxanthinones containing 3 (apo-9) to 10 (apo-8') conjugated double bonds were found upon autoxidation for all three types of astaxanthin (except free apo-8'-astaxanthinal). Fragmentation of [M + H](+) and [M + Na](+) parent masses of apo-astaxanthins from dipalmitate astaxanthin indicated palmitate esterification. Astaxanthin monopalmitate degradation resulted in a mixture of free and palmitate apo-astaxanthins. HOCl/OCl(-) rapidly converted the astaxanthins into a mixture of epoxy-apo-9- and epoxy-apo-13-astaxanthinones. The palmitate ester bond was hardly affected by autoxidation, whereas for HOCl/OCl(-) the ester bond of the apo-astaxanthin palmitoyl esters was degraded.
authors.affiliation: Laboratory of Food Chemistry, Wageningen University , P.O. Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Weesepoel
authors.forename: Harry
authors.initials: H
authors.lastname: Gruppen
authors.forename: Wouter
authors.initials: W
authors.lastname: de Bruijn
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Vincken
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004852:Epoxy Compounds / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D024341:Xanthophylls / Q000737:chemistry
chemical_list: D004852:Epoxy Compounds; D024341:Xanthophylls; C005948:astaxanthine
keywords: UHPLC-PDA-ESI-MS; apo-astaxanthins; fatty acid ester; hypochlorite bleaching; light-accelerated degradation; xanthophyll