title: Light-induced changes in an aqueous beta-carotene system stored under halogen and fluorescent lamps, affected by two oxygen partial pressures.
abstract: The aim of this work was to investigate the reaction kinetics of beta-carotene in an aqueous medium as a function of exposure to commercial lights (halogen and fluorescent sources) and oxygen partial pressures. The evolution of the pigment concentration, the changes in color, and the accumulation of a volatile compound (beta-ionone) were monitored during storage. The kinetics of degradation were mathematically modeled to compare the effects of lighting conditions and oxygen partial pressures. Lighting was also a critical variable in the presence of a low oxygen partial pressure (5 kPa), and in these conditions, the beta-carotene degraded completely during storage, even if more slowly than at 20 kPa of O2. The pigment degradation was correlated to illuminance and UVA irradiance values, but the different decay rates of the fluorescent lamps were explained by the differences in the blue region of the energy emission spectra. A halogen lamp gave minor negative effects on beta-carotene degradation.
authors.affiliation: Department of Food Science and Microbiology, University of Milan, Via Celoria 2, 20133 Milan, Italy. sara.limbo@unimi.it
authors.forename: Sara
authors.initials: S
authors.lastname: Limbo
authors.forename: Luisa
authors.initials: L
authors.lastname: Torri
authors.forename: Luciano
authors.initials: L
authors.lastname: Piergiovanni
mesh_terms: D005453:Fluorescence; D006219:Halogens; D007700:Kinetics; D008027:Light; D045792:Norisoprenoids / Q000032:analysis; D010100:Oxygen / Q000008:administration & dosage*; D010313:Partial Pressure; D012996:Solutions; D014867:Water; D019207:beta Carotene / Q000737:chemistry*
chemical_list: D006219:Halogens; D045792:Norisoprenoids; D012996:Solutions; D019207:beta Carotene; D014867:Water; C008157:beta-ionone; D010100:Oxygen