title: Changes in tocopherol and plastochromanol-8 contents in seeds and oil of oilseed rape (Brassica napus L.) during storage as influenced by temperature and air oxygen.
abstract: The changes in tocopherol and plastochromanol-8 contents in seeds and oil of oilseed rape (Brassica napus L.) were studied during a storage period of 24 weeks at different incubation temperatures and exposure to air oxygen (open and closed flasks). In the extracted oil, total tocopherol content remained unaltered at 5 and 20 degrees C throughout the 24 weeks of storage. At 40 degrees C, a beginning degradation was observed already after 4 weeks in both open and closed flasks; the alpha-tocopherol content was affected most, followed by gamma-tocopherol and plastochromanol-8. After 16 weeks at 40 degrees C, the total tocopherol content in the oil was reduced by more than 90%. In intact seeds, no tocopherol degradation was observed; only the seeds incubated at 40 degrees C and in open flasks showed slightly lower tocopherol contents. However, the analysis of the tocopherol composition in the stored seeds showed a decrease in the alpha-tocopherol content and an increase in the gamma-tocopherol content, which resulted in a decreasing alpha-/gamma-tocopherol ratio. This trend was most apparent at 40 degrees C and after 24 weeks of storage. A reduction of plastochromanol-8 occurred only at 40 degrees C and was more pronounced in open flasks. At 40 degrees C and in closed flasks a gradual increase in the content of alpha-tocotrienol was observed, a compound normally not accumulated in rapeseed.
authors.affiliation: Institute of Agronomy and Plant Breeding, Georg-August-Universität, Von-Siebold-Str. 8, D-37075 Göttingen, Germany. fgoffma@gwdg.de
authors.forename: F D
authors.initials: FD
authors.lastname: Goffman
authors.forename: C
authors.initials: C
authors.lastname: Möllers
mesh_terms: D001937:Brassica / Q000737:chemistry* / Q000196:embryology; D002839:Chromans / Q000032:analysis*; D010100:Oxygen / Q000737:chemistry; D010938:Plant Oils; D012639:Seeds; D013696:Temperature; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000032:analysis*
chemical_list: D002839:Chromans; D010938:Plant Oils; D014810:Vitamin E; C013649:plastochromanol 8; D010100:Oxygen