title: Characterization and quantification of odor-active compounds in unsaturated fatty acid/conjugated linoleic acid (UFA/CLA)-enriched butter and in conventional butter during storage and induced oxidation.
abstract: Dairy products enriched in unsaturated fatty acids (UFA) and conjugated linoleic acids (CLA) have a higher nutritional value and are suggested to have beneficial health effects. However, such acids are susceptible to oxidation, and off-flavors may be formed during storage. This study was aimed to compare the most important odorants in UFA/CLA-enriched butter to that of conventional butter during storage and induced oxidation. Volatiles were isolated by solvent-assisted flavor evaporation and identified by gas chromatography-olfactometry and mass spectrometry. Aroma extract dilution analysis revealed 18 odorants that were quantified by stable isotope dilution analysis. Another important odorant, 3-methyl-1H-indole (mothball-like odor), was quantified by high-performance liquid chromatography. After storage, UFA/CLA-enriched butter showed higher concentrations of pentanal (fatty), heptanal (green), butanoic acid (cheesy), and delta-decalactone (peach-like). Photo-oxidation of butter samples induced increases in heptanal, (E)-2-octenal, and trans-4,5-epoxy-(E)-2-decenal, especially in conventional butter. The higher vitamin content in UFA/CLA samples may protect this butter from oxidation.
authors.affiliation: Agroscope Liebefeld-Posieux Research Station ALP, Berne, Switzerland.
authors.forename: Silvia
authors.initials: S
authors.lastname: Mallia
authors.forename: Felix
authors.initials: F
authors.lastname: Escher
authors.forename: Sébastien
authors.initials: S
authors.lastname: Dubois
authors.forename: Peter
authors.initials: P
authors.lastname: Schieberle
authors.forename: Hedwig
authors.initials: H
authors.lastname: Schlichtherle-Cerny
mesh_terms: D002079:Butter / Q000032:analysis*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D005511:Food Handling; D044243:Linoleic Acids, Conjugated / Q000737:chemistry*; D009812:Odorants / Q000032:analysis*; D010084:Oxidation-Reduction; D014835:Volatilization
chemical_list: D005231:Fatty Acids, Unsaturated; D044243:Linoleic Acids, Conjugated; D002079:Butter