Categoría: Publicaciones del 2015

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

Publicada en por 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

Publicada en por 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 [...]

Distributions of phenolic acid antioxidants between the interfacial and aqueous regions of corn oil emulsions: effects of acidity and emulsifier concentration

Publicada en por antiox@uvigo.es

The oxidative stability of emulsions depends on acidity because pH may affect, among other things, the concentration of antioxidants (AOs) at the reaction site. Here we investigated the effects of pH on the partition constant, PWI, and the distribution of two phenolic acid AOs, gallic (GA) and caffeic (CA), between the aqueous (W) and interfacial (I) regions, in emulsions of 1:9 (vol:vol) corn oil/acidic water [...]

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

Publicada en por 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 [...]

To model chemical reactivity in heterogeneous emulsions: think homogeneous microemulsions

Publicada en por antiox@uvigo.es

Two important and unsolved problems in the food industry and also fundamental questions in colloid chemistry are how to measure molecular distributions, especially antioxidants (AOs), and how to model chemical reactivity, including AO efficiency in opaque emulsions. The key to understanding reactivity in organized surfactant media is that reaction mechanisms are consistent with a discrete structures–separate continuous regions duality [...]

Transfer of antioxidants at the interfaces of model food emulsions: distributions and thermodynamic parameters

Publicada en por antiox@uvigo.es

Knowledge on the driving force for the hydrophobic effect that partitions antioxidants (AOs) between the oil (O), aqueous (W) and interfacial (I) regions of food emulsions is crucial to predict their efficiency in inhibiting lipid oxidation and to preserve the organoleptic properties of lipid-based foods. Here, we have investigated the effects of temperature [...]