title: Protein distribution in lupin protein isolates from Lupinus angustifolius L. prepared by various isolation techniques.
abstract: Differences in the protein distribution of various protein isolates from Lupinus angustifolius L. Vitabor were identified as affected by the isolation procedure (alkaline and/or salt-induced extraction followed by isoelectric and/or dilutive precipitation). Protein isolates extracted in alkaline solution showed higher protein yields (26.4-31.7%) compared to salt-induced extraction (19.8-30.0%) or combined alkaline and salt-induced extraction (23.3-25.6%). Chemical variations among the protein isolates especially occurred within the albumins. Protein isolates precipitated isoelectrically showed the highest contents, whereas protein isolates precipitated by dilutive showed the lowest contents of conglutin δ. Furthermore, the alkaline subunits of conglutin α and conglutin γ decreased during alkaline extraction compared to salt-induced extraction. A decrease in protein-bound polar and basic amino acids was shown after protein isolation. In contrast, the amounts of nonpolar, aliphatic, aromatic, hydroxylated and sulfur-rich amino acids were higher in the lupin protein isolates compared to the lupin flakes. However, the functional side chains could not be related to the specific molecular arrangements of the protein isolates, as a similar amino acid composition was found among the protein isolates.
authors.affiliation: Fraunhofer Institute for Process Engineering and Packaging (IVV), Giggenhauser Strasse 35, D-85354 Freising, Germany. Electronic address: isabel.muranyi@ivv.fraunhofer.de.
authors.forename: Isabel S
authors.initials: IS
authors.lastname: Muranyi
authors.affiliation: Center for Biotechnology and Biomedicine, Faculty of Chemistry and Mineralogy, University Leipzig, Deutscher Platz 5, D-04103 Leipzig, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Volke
authors.affiliation: Center for Biotechnology and Biomedicine, Faculty of Chemistry and Mineralogy, University Leipzig, Deutscher Platz 5, D-04103 Leipzig, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Hoffmann
authors.affiliation: Fraunhofer Institute for Process Engineering and Packaging (IVV), Giggenhauser Strasse 35, D-85354 Freising, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Eisner
authors.affiliation: Fraunhofer Institute for Process Engineering and Packaging (IVV), Giggenhauser Strasse 35, D-85354 Freising, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Herfellner
authors.affiliation: German Research Centre for Food Chemistry, Lise-Meitner-Strasse 34, D-85354 Freising, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Brunnbauer
authors.affiliation: German Research Centre for Food Chemistry, Lise-Meitner-Strasse 34, D-85354 Freising, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Koehler
authors.affiliation: Fraunhofer Institute for Process Engineering and Packaging (IVV), Giggenhauser Strasse 35, D-85354 Freising, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Schweiggert-Weisz
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D031297:Lupinus / Q000737:chemistry*; D008970:Molecular Weight
keywords: Albumin; Conglutin; Lupinus angustifolius L.; Molecular weight; Protein yield; Proteins studied in this article are α-conglutin (NCBInr: 2313076); Sodium dodecyl sulfate-polyacrylamide gel electrophoresis; β-Conglutin (NCBInr: 149208403, 149208401, 169950562); γ-Conglutin (NCBInr: 662366); γ-Conglutin smaller subunit (NCBInr: 223005); δ-Conglutin-2 large chain (NCBInr: 116181)