title: Interfacial Concentrations of Hydroxytyrosol and Its Lipophilic Esters in Intact Olive Oil-in-Water Emulsions: Effects of Antioxidant Hydrophobicity, Surfactant Concentration, and the Oil-to-Water Ratio on the Oxidative Stability of the Emulsions.
abstract: We determined the interfacial molarities of the antioxidants, AOs, hydroxytyrosol (HT), and HT fatty acid esters with chain lengths of 1 to 16 carbons in intact olive oil/water/Tween 20 emulsions. The results were compared with chain length effects on the oxidative stability of the same emulsions, and a direct correlation was established. Both (AOI) molarities (varying 50-250 times greater than the stoichiometric 3.5 × 10(-3) M AO concentration) and antioxidant efficiencies show similar parabola-like dependences on AO chain length with a maximum at C8, consistent with the "cut-off" effect often observed at longer chain lengths. Results should aid in understanding the complex structure-reactivity relationships between AO efficiencies in emulsified systems and their hydrophobilic-hydrophobic balance.
authors.affiliation: REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , 4169-007 Porto, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Almeida
authors.affiliation: REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , 4169-007 Porto, Portugal.|Universidad de Vigo , Fac. Química, Dpto Química Física, 36200 Vigo, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Losada-Barreiro
authors.affiliation: REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , 4169-007 Porto, Portugal.
authors.forename: Marlene
authors.initials: M
authors.lastname: Costa
authors.affiliation: REQUIMTE-LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , 4169-007 Porto, Portugal.
authors.forename: Fátima
authors.initials: F
authors.lastname: Paiva-Martins
authors.affiliation: Universidad de Vigo , Fac. Química, Dpto Química Física, 36200 Vigo, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Bravo-Díaz
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey , Piscataway, New Jersey 08854, United States.
authors.forename: Laurence S
authors.initials: LS
authors.lastname: Romsted
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry; D004952:Esters / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D000069463:Olive Oil / Q000737:chemistry*; D010084:Oxidation-Reduction; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D004655:Emulsions; D004952:Esters; D000069463:Olive Oil; D013501:Surface-Active Agents; D014867:Water; C005975:3,4-dihydroxyphenylethanol; D010626:Phenylethyl Alcohol
keywords: antioxidant efficiency; fatty acid esters; hydroxytyrosol