title: "Cut-off" effect of antioxidants and/or probes of variable lipophilicity in microheterogeneous media.
abstract: The activities of two hydrophilic (ascorbic acid and Trolox) and two hydrophobic (α-tocopherol and BHT) antioxidants were measured by reaction with a series of 4-alkanoyloxyTEMPO radical probes 1 in buffered (pH 7), aqueous, micellar solutions of reduced Triton-X 100. In all cases, a cut-off effect was observed, in line with previous observations of the same effect for the partitioning of probe series 1 in this medium. These results support an interpretation of the cut-off effect in food emulsions, based on the "amphiphobic" nature of either the antioxidants or probes: competition between two molecular moieties, for the micellar hydrophobic core, tends to expose a reacting fragment differently to a more hydrophilic microenvironment, as the probe or antioxidant hydrophobicity increases.
authors.affiliation: Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago de Chile, Chile; Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Chile. Electronic address: carolina.aliaga@usach.cl.
authors.forename: Carolina
authors.initials: C
authors.lastname: Aliaga
authors.affiliation: Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago de Chile, Chile.
authors.forename: Amaia
authors.initials: A
authors.lastname: López de Arbina
authors.affiliation: Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago de Chile, Chile.
authors.forename: Marcos Caroli
authors.initials: MC
authors.lastname: Rezende
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D001205:Ascorbic Acid / Q000737:chemistry; D002084:Butylated Hydroxytoluene / Q000737:chemistry; D002839:Chromans / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D010084:Oxidation-Reduction; D024502:alpha-Tocopherol / Q000737:chemistry
chemical_list: D000975:Antioxidants; D002839:Chromans; D008823:Micelles; D002084:Butylated Hydroxytoluene; D024502:alpha-Tocopherol; D001205:Ascorbic Acid; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid
keywords: 4-AlkanoyloxyTEMPO; Antioxidant activity; Ascorbate; BHT; EPR; Hydrophobicity; Micelle; Trolox; α-Tocopherol