title: Formation of aroma compounds and lipoxygenase (EC 1.13.11.12) activity in unblanched leek (Allium ampeloprasum Var. Bulga) slices during long-term frozen storage.
abstract: The content of aroma compounds (dynamic headspace) and catalytic activity of lipoxygenase (LOX) (EC. 1.13.11.12) were analyzed in 15 mm unblanched leek slices seven times during 12 months of frozen storage. The aroma profile changed from consisting of almost only sulfur compounds such as dipropyl disulfide [concentration in fresh leek (FL) = 0.197 mg/L, concentration after 12 months of frozen storage (12M) = 0.0409 mg/L] and propyl (E)-propenyl disulfide (FL = 0.0437 mg/L, 12M = 0.00452 mg/L) in the fresh leeks to being dominated by numerous saturated and unsaturated aldehydes, such as hexanal (FL = 1.53 mg/L, 12M = 3.63 mg/L), (E,E)-2,4-nonadienal (FL = 0.000 mg/L, 12M = 0.0647 mg/L), and (E,E)-2,4-decadienal (FL = 0.129 mg/L, 12M = 0.594 mg/L) at the end of the storage period. The catalytic activity of LOX diminished throughout frozen storage, but approximately 25% of the original activity was present after 12 months of storage.
authors.affiliation: Department of Dairy and Food Science, Centre of Advanced Food Studies, The Royal Veterinary and Agricultural University, Rolighedsvej 30, 1958 Frederiksberg C, Denmark.
authors.forename: Ghita Studsgaard
authors.initials: GS
authors.lastname: Nielsen
authors.forename: Lone Melchior
authors.initials: LM
authors.lastname: Larsen
authors.forename: Leif
authors.initials: L
authors.lastname: Poll
mesh_terms: D000447:Aldehydes / Q000032:analysis; D000490:Allium / Q000737:chemistry* / Q000201:enzymology*; D005628:Frozen Foods / Q000032:analysis*; D008084:Lipoxygenase / Q000378:metabolism*; D009812:Odorants / Q000032:analysis*; D013457:Sulfur Compounds / Q000032:analysis
chemical_list: D000447:Aldehydes; D013457:Sulfur Compounds; D008084:Lipoxygenase