title: Electron paramagnetic resonance study of hydrogen peroxide/ascorbic acid ratio as initiator redox pair in the inulin-gallic acid molecular grafting reaction.
abstract: Gallic acid (GA) was grafted onto inulin using the free radicals method, generated by the hydrogen peroxide/ascorbic acid (H2O2/AA) redox pair. Molar ratios of H2O2/AA at 9, 20, 39 and 49 were evaluated by Electron Paramagnetic Resonance in order to find the effect of the oxidation of the inulin and the efficiency in the inulin-gallic acid grafting (IGA). The highest concentration of the inulin macro-radical was obtained with H2O2/AA molar ratios of 20 and 49 with the removal of a hydrogen atom from a methyl group of the inulin fructose monomers. The highest grafting ratio (30.4 mg GA eq/g IGA) was obtained at 9 M of H2O2/AA. UV-Vis, FT-IR-ATR and XDR results confirmed a successful IGA grafting. The efficiency of the grafting reaction depends on the concentration of the macro-radical, it depends on the molar ratio of H2O2/AA, being affected by simultaneous reactions between components of the mixture (H2O2, AA, inulin, GA and eventually atmospheric oxygen) as well.
authors.affiliation: Facultad de Ciencias Agrícolas, Universidad Autónoma del Estado de México, Campus Universitario "El Cerrillo", Km 15, Carr. Toluca-Ixtlahuaca, Entronque El Cerrillo, Apdo, Postal 435, Toluca 50200, Estado de México, Mexico. Electronic address: arcoda21@gmail.com.
authors.forename: Daniel
authors.initials: D
authors.lastname: Arizmendi-Cotero
authors.affiliation: Centro Conjunto de Investigación en Química Sustentable, Universidad Autónoma del Estado de México, Universidad Nacional Autónoma de México, Carretera Toluca-Atlacomulco, km 14.5, Toluca 50200, Estado de México, Mexico. Electronic address: rosamarigo@gmail.com.
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Gómez-Espinosa
authors.affiliation: Facultad de Química, Universidad Autónoma del Estado de México, Avenida Paseo Tollocan S/N, Toluca 50180, Estado de México, Mexico. Electronic address: octavio_dublan@yahoo.com.mx.
authors.forename: Octavio
authors.initials: O
authors.lastname: Dublán García
authors.affiliation: Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Delegación Coyoacán, C.P. 04510, México, D.F., Mexico. Electronic address: gomvidal@unam.mx.
authors.forename: Virginia
authors.initials: V
authors.lastname: Gómez-Vidales
authors.affiliation: Facultad de Ciencias Agrícolas, Universidad Autónoma del Estado de México, Campus Universitario "El Cerrillo", Km 15, Carr. Toluca-Ixtlahuaca, Entronque El Cerrillo, Apdo, Postal 435, Toluca 50200, Estado de México, Mexico. Electronic address: adominguezl@uaemex.mx.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Dominguez-Lopez
keywords: Antioxidants; Electron paramagnetic resonance; Inulin; Molecular grafting; Phenolic compounds; Prebiotics