title: Light-induced oxidation in semihard cheeses. Evaluation of methods used to determine levels of oxidation.
abstract: Light-induced oxidation in Havarti cheese (38% fat) stored in the dark and exposed to fluorescent light was evaluated by an array of chemical, physical, and spectroscopic methods. Light-induced changes were noticeable already after short exposure times (<12 h). A clear differentiation between samples stored in the dark and samples exposed to 1000 lx fluorescent light was obtained by means of the following methods: color measurements (a values), peroxide value determinations, and evaluations of volatile oxidation products by solid-phase microextraction gas chromatography (SPME-GC). The expected changes in peroxide values in relation to storage time were not evident. Measuring free radicals by electron spin resonance spectrometry could not be done to distinguish between samples, possibly due to the conversion of radicals during sample preparation. However, significant light-exposure effects on secondary oxidation products, detected by SPME-GC, were noted for 1-pentanol, 1-hexanol, nonanal, and benzaldehyde.
authors.affiliation: Arla Foods Innovation, Rørdrumvej 2, DK-8220 Brabrand, Denmark, CP Kelco, Ved Banen 16, DK-4623 Lille Skensved, Denmark.
authors.forename: Grith
authors.initials: G
authors.lastname: Mortensen
authors.forename: John
authors.initials: J
authors.lastname: Sørensen
authors.forename: Henrik
authors.initials: H
authors.lastname: Stapelfeldt
mesh_terms: D000438:Alcohols / Q000032:analysis; D000447:Aldehydes / Q000032:analysis; D002611:Cheese / Q000032:analysis*; D002849:Chromatography, Gas; D003116:Color; D005227:Fatty Acids / Q000032:analysis; D005609:Free Radicals / Q000737:chemistry; D008027:Light; D009812:Odorants; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis; D010545:Peroxides / Q000032:analysis; D014835:Volatilization
chemical_list: D000438:Alcohols; D000447:Aldehydes; D005227:Fatty Acids; D005609:Free Radicals; D010545:Peroxides; D010100:Oxygen