title: Oxidative stability of bovine serum albumin- and sodium caseinate-stabilized emulsions depends on metal availability.
abstract: Proteins often stabilize food emulsions and are also able to promote or delay lipid oxidation in complex systems. The purpose of this work was to investigate the relationship between metal ion availability and oxidative stability of oil-in-water emulsions stabilized by bovine serum albumin (BSA) or sodium caseinate (NaCas). Emulsions with similar and stable droplet size distributions were prepared with stripped sunflower oil (30 vol %) and protein solutions (20 g L(-)(1); pH = 6.5). In the absence of the water-soluble metal chelator EDTA, oxygen uptake, conjugated dienes, and volatile compounds developed faster in NaCas-stabilized emulsions than in those prepared with BSA. This effect is attributed to the chelating properties of NaCas and to electrostatic interactions that attract some metal ions at the interface where they could initiate lipid oxidation. When EDTA (100 muM) was present, oxidation was delayed to a greater extent in emulsions made with NaCas than in BSA stabilized emulsions. These conditions probably enabled NaCas to exert free-radical-scavenging activity.
authors.affiliation: INRA - Laboratoire d'Etude des Interactions des Molécules Alimentaires, Rue de la Géraudière BP 71627 - F 44316 NANTES Cedex 3, France.
authors.forename: Angélique
authors.initials: A
authors.lastname: Villiere
authors.forename: Michèle
authors.initials: M
authors.lastname: Viau
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bronnec
authors.forename: Nathalie
authors.initials: N
authors.lastname: Moreau
authors.forename: Claude
authors.initials: C
authors.lastname: Genot
mesh_terms: D002364:Caseins / Q000737:chemistry* / Q000378:metabolism; D002614:Chelating Agents / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004355:Drug Stability; D004492:Edetic Acid / Q000494:pharmacology; D004655:Emulsions / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D008670:Metals / Q000737:chemistry*; D010084:Oxidation-Reduction; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism; D055672:Static Electricity
chemical_list: D002364:Caseins; D002614:Chelating Agents; D004655:Emulsions; D016166:Free Radical Scavengers; D008670:Metals; D012710:Serum Albumin, Bovine; D004492:Edetic Acid; D007501:Iron