The location of amphiphobic antioxidants in micellar systems: the diving-swan analogy

Posted on 5 December, 201814 February, 2019 by antiox@uvigo.es

05 December 2018 Food Chemistry. 1 - 279, pp. 288 - 293. 2018 Sonia Losada-Barreiroc, Amaia Lopez de Arbinaa,b, Marcos Caroli Rezendea, Matias Vidala, Carolina Aliagaa,b* Autor affilations: *Corresponding authors aFacultad de Química y Biología, Universidad de Santiago de Chile, Av. B.O’Higgins 3363, Santiago, Chile bCentro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Read more about The location of amphiphobic antioxidants in micellar systems: the diving-swan analogy[...] [...]

Using pseudophase models to determine antioxidant distributions in emulsions: why dynamic equilibrium matters

Posted on 23 April, 20172 January, 2019 by antiox@uvigo.es

Distributions of a homologous series of protocatechuic acid (PCA) derivatives of increasing lipophilicity were determined in stripped soybean oil-in-water emulsions and compared with their antioxidant (AO) efficiencies. The distribution was determined by employing a recently developed a kinetic method, based on the reaction between the hydrophobic 4-hexadecylbenzenediazonium ions (16-ArN2+) and the antioxidants [...]

Free radicals and polyphenols: The redox chemistry of neurodegenerative diseases

Posted on 29 March, 201710 May, 2017 by antiox@uvigo.es

The oxidation of bioorganic materials by air and, particularly, the oxidative stress involved in the cell loss and other pathologies associated with neurodegenerative diseases (NDs) are of enormous social and economic importance. NDs generally involve free radical reactions, beginning with the formation of an initiating radical by some redox, thermal or photochemical process [...]

Kinetic evidence for the formation of diazo ethers in the course of reactions between arenediazonium ions and antioxidants

Posted on 10 February, 201714 May, 2017 by antiox@uvigo.es

The reactions between arenediazonium ions, ArN2+, and phenolic antioxidants, AOs, are of interest because ArN2+ are involved in carcinogenic and mutagenic processes in contrast to phenolic AOs, that have biological activity and potential beneficial effects on health, and because an ArN2+ is currently being employed as a chemical probe to assess the distribution of AOs in lipid-based food emulsions [...]

A physicochemical study of the effects of acidity on the distribution and antioxidant efficiency of Trolox in olive-oil in water emulsions

Posted on 18 January, 201611 May, 2017 by antiox@uvigo.es

The efficiency of antioxidants to inhibit the oxidation of lipid-based emulsions depends on several factors including their nature and their concentration at the reaction site. Here, we have analyzed the effects of acidity and of surfactant concentration on the distribution and efficiency of the vitamin E analog Trolox (TR) in stripped olive oil-in-water emulsions stabilized with Tween 20 [...]

Encapsulation and solubilization of antioxidants gallic acid and ethyl, propyl and butyl gallate with B-cyclodextrin

Posted on 1 October, 201511 May, 2017 by antiox@uvigo.es

We investigated the formation of inclusion complexes of the antioxidants (AOs) gallic acid, GA, and its hydrophobic derivatives ethyl (EG), propyl (PG) and butyl (BG) gallate with β-cyclodextrin (β-CD) by employing the UV spectral shifts method and, for the sake of comparisons, a modified phase-solubility method that exploits the use of a competitive guest molecule (acetonitrile, ACN) that completely removes the antioxidants from the CD cavity and, at the same time, keeps them in solution [...]

Interfacial kinetics in octane based emulsions. Effects of surfactant concentration on the reaction between 16-ArN2+ and octyl and lauryl gallates

Posted on 5 September, 201514 May, 2017 by antiox@uvigo.es

Here we have applied the formalism of the pseudophase kinetic model to analyze the reactivity of 4-hexadecylbenzenediazonium, 16-ArN2+, ions with the antioxidants octyl gallate (OG) and lauryl gallate (LG) in emulsions composed of octane, acidic water and hexaetyleneglycol monododecyl ether, C12E6 [...]

A direct correlation between the antioxidant efficiencies of caffeic acid and its alkyl esters and their concentrations in the interfacial region of olive oil emulsions. The pseudophase model interpretation of the “cut-off” effect

Posted on 15 May, 201511 May, 2017 by antiox@uvigo.es

Recently published results for a series of homologous antioxidants, AOs, of increasing alkyl chain length show a maximum in AO efficiency followed by a significant decrease for the more hydrophobic AOs, typically called the "cut-off" effect. Here we demonstrate that in olive oil emulsions both antioxidant efficiencies [...]

Influence of temperature on the distribution of catechin in corn oil-in water emulsions and some relevant thermodynamic parameters

Posted on 25 March, 201414 May, 2017 by antiox@uvigo.es

We investigated the effects of increasing temperature and emulsifier volume fraction (ΦI) on the distribution of catechin (CAT) in stripped corn oil-in-water emulsions. We also estimated relevant thermodynamic parameters for the transfer of CAT from the aqueous to the interfacial region because CAT is sparingly soluble in corn oil and mainly distributes between the aqueous and interfacial regions of emulsions [...]

Effects of acidity, temperature and emulsifier concentration on the distribution of caffeic acid in stripped corn and olive oil in water emulsions

Posted on 9 August, 201314 May, 2017 by antiox@uvigo.es

We evaluated the effects of oil type, oil to water ratio, emulsifier concentration, acidity, and temperature on the distribution of caffeic acid, CA, in emulsions composed of stripped olive and corn oils, acidic water, and Tween 20. CA mainly distributes between the water and interfacial regions because it is sparingly soluble in oils, as demonstrated by auxiliary partitioning experiments in the absence of an emulsifier [...]