title: Molecular characterization of whey protein hydrolysate fractions with ferrous chelating and enhanced iron solubility capabilities.
abstract: The ferrous (Fe2+) chelating capabilities of WPI hydrolysate fractions produced via cascade membrane filtration were investigated, specifically 1 kDa permeate (P) and 30 kDa retentate (R) fractions. The 1 kDa-P possessed a Fe2+ chelating capability at 1 g L(-1) equivalent to 84.4 μM EDTA (for 30 kDa-R the value was 8.7 μM EDTA). Fourier transformed infrared (FTIR) spectroscopy was utilized to investigate the structural characteristics of hydrolysates and molecular interactions with Fe2+. Solid-phase extraction was employed to enrich for chelating activity; the most potent chelating fraction was enriched in histidine and lysine. The solubility of ferrous sulfate solutions (10 mM) over a range of pH values was significantly (P<0.05) improved in dispersions of hydrolysate fraction solutions (10 g protein L(-1)). Total iron solubility was improved by 72% in the presence of the 1 kDa-P fraction following simulated gastrointestinal digestion (SGID) compared to control FeSO4·7H2O solutions.
authors.affiliation: †Teagasc Food Research Centre, Moorepark, Fermoy, County Cork, Ireland.|§Life Sciences Department, University of Limerick, Limerick, Ireland.
authors.forename: Ian B
authors.initials: IB
authors.lastname: O'Loughlin
authors.affiliation: †Teagasc Food Research Centre, Moorepark, Fermoy, County Cork, Ireland.
authors.forename: Phil M
authors.initials: PM
authors.lastname: Kelly
authors.affiliation: †Teagasc Food Research Centre, Moorepark, Fermoy, County Cork, Ireland.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Murray
authors.affiliation: §Life Sciences Department, University of Limerick, Limerick, Ireland.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: FitzGerald
authors.affiliation: †Teagasc Food Research Centre, Moorepark, Fermoy, County Cork, Ireland.
authors.forename: Andre
authors.initials: A
authors.lastname: Brodkorb
mesh_terms: D002614:Chelating Agents / Q000737:chemistry; D004063:Digestion; D005296:Ferrous Compounds / Q000737:chemistry; D006801:Humans; D007501:Iron / Q000737:chemistry* / Q000378:metabolism; D008894:Milk Proteins / Q000737:chemistry* / Q000378:metabolism; D008954:Models, Biological; D011492:Protein Hydrolysates / Q000737:chemistry / Q000378:metabolism; D012995:Solubility; D000067816:Whey Proteins
chemical_list: D002614:Chelating Agents; D005296:Ferrous Compounds; D008894:Milk Proteins; D011492:Protein Hydrolysates; D000067816:Whey Proteins; C020748:ferrous sulfate; D007501:Iron
keywords: FTIR; enzymatic hydrolysis; iron-binding; simulated digestion; whey protein