Categoría: Publicacion

Effects of acidity and emulsifier concentration on the distribution of Vitamin C in a model food emulsion

Publicada en por antiox@uvigo.es

We have analyzed the effects of acidity and emulsifier concentration on the distribution of ascorbic acid or vitamin C (VC) in a model emulsion prepared by mixing octane, acidic (HCl) water and the non-ionic surfactant hexaethyleneglycol monododecyl ether (C12E6). VC is oil insoluble, and only the partition constant between the interfacial and aqueous regions (PWI) is needed to describe its distribution within the emulsion [...]

Temperature and emulsifier concentration effects on gallic acid distribution in a model food emulsion

Publicada en por antiox@uvigo.es

We determined the effects of emulsifier concentration and temperature on the distribution of gallic acid (GA) in a food-grade emulsion composed of 1:9 vol:vol stripped corn oil, acidic water and Tween 20. The distribution of GA can be defined by the partition constant between the aqueous and the interfacial regions, View the MathML source, which was determined by using a kinetic method and the pseudophase kinetic model [...]

Distribution of Tert-Butylhydroquinone in a Corn Oil/C12E6/Water Based Emulsion. Application of the Pseudophase Kinetic Model

Publicada en por antiox@uvigo.es

We have determined the distribution of the antioxidant tert-butylhydroquinone, TBHQ, between the oil and interfacial regions of an emulsion composed of stripped corn oil, acidic water and hexaethyleneglycol monododecyl ether, C12E6, by employing a kinetic method based on the reaction between the hydrophobic 16-hexadecylbenzenediazonium ions, 16-ArN2+, and TBHQ [...]

Butanolysis of 4-methylbenzenediazonium ions in binary n-BuOH/H2O mixtures and in n-BuOH/SDS/H2O reverse micelles. Effects of solvent composition, acidity and temperature on the switch between heterolytic and homolytic dediazoniation mechanisms

Publicada en por antiox@uvigo.es

We investigated the effects of solvent composition, acidity and temperature on the switch between heterolytic and homolytic mechanisms in the course [...]

Reactivity of 3-Methylbenzenediazonium ions with Gallic Acid. Kinetics and Mechanism of the Reaction

Publicada en por antiox@uvigo.es

We investigated the kinetics and mechanism of the reaction between the 3-methylbenzenediazonium ions (3MBD), and gallic acids (=3,4,5-trihydroxybenzoic acid; GA) in aqueous buffer solution under acidic conditions by employing spectrometric, electrochemical, and chromatographic techniques and computational methods [...]

Effects of Temperature and Emulsifier Concentration on α-Tocopherol Distribution in a Stirred, Fluid, Emulsion. Thermodynamics of α-Tocopherol Transfer between the Oil and Interfacial Regions

Publicada en por antiox@uvigo.es

The combined linear sweep voltammetry (LSV)/pseudophase kinetic model method was used to obtain the first estimates of the free energies, enthalpy, and entropies of transfer of α-tocopherol (TOC) between the oil and interfacial regions of fluid, opaque, emulsions of n-octane [...]

Dediazoniation of 1-naphthalenediazonium tetrafluoroborate in aqueous acid and in micellar solutions

Publicada en por antiox@uvigo.es

We have measured the rates and product yields of dediazoniation of 1-naphthalenediazonium (1ND) tetrafluoroborate in the presence and absence of sodium dodecyl sulfate (SDS) micellar aggregates by employing a combination of UV–vis spectroscopy and high-performance liquid chromatography [...]

Micellar effects on the reaction between an arenediazonium ion and the antioxidants gallic acid and octyl gallate

Publicada en por antiox@uvigo.es

The effect of sodium dodecyl sulfate (SDS) micelles on the reaction between the 3-methylbenzenediazonium (3MBD) ion and either the hydrophilic antioxidant gallic acid (GA) or the hydrophobic analogue octyl gallate (OG) have been investigated as a function of pH [...]

Kinetic and Mechanism of the reaction between 4-hexadecylbenzenediazonium ions and vitamin C in emulsions: Further evidence of the formation of diazo ether intermediates in the course of the reaction

Publicada en por antiox@uvigo.es

The kinetics and mechanism of the reaction between hydrophobic 4-hexadecylarenediazonium ions, 16-ArNmath image and vitamin C, VC, in a model emulsion prepared by mixing octane, acidic (HCl) water and the non-ionic surfactant hexaethyleneglycol monododecyl ether, C12E6, were investigated [...]

Quantitative determination of alpha-tocopherol distribution in a tributyrin/Brij 30/water model food emulsion

Publicada en por antiox@uvigo.es

Until recently, determining the distribution of antioxidants, AOs, between the oil, interfacial and aqueous regions of opaque emulsions has not worked well because the concentrations of AOs in interfacial regions cannot be determined separately from their concentrations in the oil and water phases [...]