title: Lipoxygenase activity in different species of sweet lupin (Lupinus L.) seeds and flakes.
abstract: Lipoxygenase (LOX)-catalysed degradation of polyunsaturated fatty acids is supposed to be a major cause of undesirable off-flavour development in legumes. In the present study, a photometric LOX assay including adequate sample workup was adapted to lupin seeds, kernels and flakes, respectively. Optimum reaction conditions were at pH 7.5 using a phosphate buffer concentration of 150 mmol l(-1) without the addition of sodium chloride. The LOX activities of different lupin species and varieties were compared. Significant variations among the species and varieties ranging from 50 to 1004 units mg(-1) protein were determined, being significantly lower than soybean LOX activity. Hulling and flaking of the seeds resulted in a 15% increase of LOX activity. In contrast to soy and other legumes, LOX from lupin only converted free fatty acids, whereas trilinolein and β-carotene were not oxidised. Consequently, according to the established classification, lupin LOX activity may be assigned to the LOX type-1, which, to the best of our knowledge, was demonstrated for the first time.
authors.affiliation: Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Straße 35, 85354 Freising, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Stephany
authors.affiliation: Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Straße 35, 85354 Freising, Germany. Electronic address: stephanie.mittermaier@ivv.fraunhofer.de.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Bader-Mittermaier
authors.affiliation: Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Straße 35, 85354 Freising, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Schweiggert-Weisz
authors.affiliation: Institute of Food Technology, Chair Plant Foodstuff Technology, Hohenheim University, Garbenstraße 25, 70599 Stuttgart, Germany; King Abdulaziz University, Biological Science Department, Faculty of Science, P.O. Box 80257, Jeddah 21589, Saudi Arabia.
authors.forename: Reinhold
authors.initials: R
authors.lastname: Carle
mesh_terms: D005231:Fatty Acids, Unsaturated / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008084:Lipoxygenase / Q000378:metabolism*; D031297:Lupinus / Q000201:enzymology*; D012639:Seeds / Q000201:enzymology*; D013025:Glycine max / Q000201:enzymology; D014280:Triglycerides / Q000737:chemistry; D019207:beta Carotene / Q000737:chemistry
chemical_list: D005231:Fatty Acids, Unsaturated; D014280:Triglycerides; D019207:beta Carotene; D008084:Lipoxygenase; C009564:trilinolein
keywords: Crude enzyme extract; Isoenzymes; Lipid oxidation; Lipoxygenase; Lupinus angustifolius L.