title: [Carbonyl compounds from the reaction of barley isomerase with linoleic acid hydroperoxides. Their development from the 9- or the 13-hydroperoxide-isomer (author's transl)].
abstract: Hydroperoxid isomerase from barley was incubated with linoleic acid hydroperoxides (LHPO), containing nearly exclusively the 13-LHPO or the 9-LHPO isomer; the volatile reaction products were isolated, concentrated and investigated by means of gas and radio-gaschromatography. Thus it was possible to establish the precursors of the volatile compounds hexanal, 2-trans-heptenal and 2-trans-octenal, which develop during formerly described reactions of isomerase with substrates, containing 9- and 13-LHPO in equal amounts. 13-LHPO was found to be a precursor of hexanal and 2-tr-octenal, while the 9-LHPO isomer in the barley isomerase LHPO breakdown reaction obviously cannot be accepted as precursor of volatile components. The origin of 2-tr-heptenal could not be clarified; it occured neither in the experiments with predominating 9-LHPO nor in those with predominating 13-LHPO. Perhaps 2-tr-heptenal is only produced in the presence of a defined ratio of both isomeric hydroperoxides.
  
  
  BACKGROUND
  13-LHPO = 13-hydroperoxy-9-cis, 11-trans-octadecadienoic acid. 9-LHPO = 9-hydroperoxy-10-trans, 12-cis-octadecadienoic acid.
mesh_terms: D002264:Carboxylic Acids; D002523:Edible Grain / Q000201:enzymology*; D001467:Hordeum / Q000201:enzymology*; D007202:Indicators and Reagents; D007535:Isomerases; D007536:Isomerism; D008041:Linoleic Acids; D010545:Peroxides
chemical_list: D002264:Carboxylic Acids; D007202:Indicators and Reagents; D008041:Linoleic Acids; D010545:Peroxides; D007535:Isomerases
vernacular_title: Flüchtige Carbonylverbindungen aus der Reaktion von Gerstenisomerase mit Linolsäurehydroperoxiden. Ihre Entstehung aus den 9- oder 13-Hydroperoxid-Isomeren.