title: Effects of ozone and oxygen on the degradation of carotenoids in an aqueous model system.
abstract: The effects of ozone and oxygen on the degradation of carotenoids in an aqueous model system were studied. All-trans beta-carotene, 9-cis beta-carotene, beta-cryptoxanthin, and lycopene were adsorbed onto a C(18) solid phase and exposed to a continuous flow of water saturated with oxygen or ozone at 30 degrees C. Carotenoids were analyzed using HPLC with a C(30) column and a photodiode array detector. Approximately 90% of all-trans beta-carotene, 9-cis beta-carotene, and beta-cryptoxanthin were lost after exposure to ozone for 7 h. A similar loss of lycopene occurred in only 1 h. When exposed to oxygen, all carotenoids, except beta-cryptoxanthin, degraded at lower rates. The degradation of all the carotenoids followed zero-order reaction kinetics with the following relative rates: lycopene > beta-cryptoxanthin > all-trans beta-carotene > 9-cis beta-carotene. The major degradation products of beta-carotene were tentatively identified on the basis of their elution on the HPLC column, UV-Vis spectra, and electrospray LC-MS. Predominant isomers of beta-carotene were 13-cis, 9-cis, and a di-cis isomer. Products resulting from cleavage of the molecule were beta-apo-13-carotenone and beta-apo-14'-carotenal, whereas epoxidation yielded beta-carotene 5,8-epoxide and beta-carotene 5, 8-endoperoxide.
authors.affiliation: Department of Food Science, Post Office Box 7624, North Carolina State University, Raleigh, North Carolina 27695-7624, USA.
authors.forename: L K
authors.initials: LK
authors.lastname: Henry
authors.forename: N L
authors.initials: NL
authors.lastname: Puspitasari-Nienaber
authors.forename: M
authors.initials: M
authors.lastname: Jarén-Galán
authors.forename: R B
authors.initials: RB
authors.lastname: van Breemen
authors.forename: G L
authors.initials: GL
authors.lastname: Catignani
authors.forename: S J
authors.initials: SJ
authors.lastname: Schwartz
mesh_terms: D002338:Carotenoids / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D007700:Kinetics; D013058:Mass Spectrometry; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*
chemical_list: D002338:Carotenoids; D010126:Ozone; D010100:Oxygen