title: Degradation of non-esterified and esterified xanthophylls by free radicals.
abstract: beta-Carotene and other xanthophylls present in pepper fruit as both free and esterified forms were oxidized using a free radical initiator (2,2'-azo-bis-isobutyronitrile). Capsorubin was degraded most slowly, followed by zeaxanthin, capsanthin, and beta-carotene. The presence of keto groups at the ends of the polyene chain could be a structural factor contributing to this difference in reactivity. It was also shown that whereas capsanthin and its esters and capsorubin and its esters were degraded at the same rate, zeaxanthin esters responded differently to the oxidation process, and were degraded more quickly than free zeaxanthin. The presence of unsaturated fatty acids (mainly linoleic) that esterify zeaxanthin help to accelerate the degradation of this xanthophyll and decreasing its antioxidant action. The antioxidant capacity of capsorubin and capsanthin (both in free and esterified form) exclusive to the genus capsicum should be taken into account.
authors.affiliation: Departamento de Biotecnologija de Alimentos, Instituto de la Grasa (CSIC), Avenida Padre Garcija Tejero, 4, 41012 Sevilla, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Pérez-Gálvez
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Mínguez-Mosquera
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D002338:Carotenoids / Q000737:chemistry; D004951:Esterification; D005609:Free Radicals; D009570:Nitriles; D010084:Oxidation-Reduction; D024341:Xanthophylls / Q000737:chemistry*; D065146:Zeaxanthins; D019207:beta Carotene / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D009570:Nitriles; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene; D002338:Carotenoids; C006889:capsanthin; C035624:capsorubin; C004526:azobis(isobutyronitrile)