title: Electrochemical characterization of gelatinized starch dispersions: voltammetry and electrochemical impedance spectroscopy on platinum surface.
abstract: The electrochemical properties of gelatinized starch dispersions (GSD; 5% w/w) from different botanical sources were studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests over a platinum surface. The phenomenological modelling of EIS data using equivalent circuits indicated that after gelatinization the electrical resistance was determined mainly by the resistance of insoluble material (i.e., ghosts). Sonication of the GSD disrupted the ghost microstructure, and produced an increase in electrical conductivity by reducing the resistance of the insoluble material. The CV data showed three oxidation peaks at potentials where glucose solutions displayed oxidation waves. It is postulated that hydrolysis at the bulk and electrocatalyzed oxidation on the Pt-surface are reactions involved in the starch transformation. Starches peak intensity increased with the amylose content, suggesting that the amylose-rich matrix played an important role in the charge transfer in the electrolytic system.
authors.affiliation: Departamento de Ingeniería Agroindustrial, Posgrado en Ciencia y Tecnología Agroalimentaria, Universidad Autónoma Chapingo, Km 38.5 Carretera México-Texcoco, Texcoco 56230, Mexico.
authors.forename: C
authors.initials: C
authors.lastname: Hernandez-Jaimes
authors.affiliation: Departamento de Preparatoria Agrícola, Universidad Autónoma Chapingo, Km 38.5 Carretera México-Texcoco, Texcoco 56230, Mexico.
authors.forename: C
authors.initials: C
authors.lastname: Lobato-Calleros
authors.affiliation: Instituto Mexicano del Petróleo, Programa de Investigación en Integridad de Ductos, Lázaro Cárdenas No. 152, Col. San Bartolo Atepehuacan, México, D.F. 07730, Mexico.
authors.forename: E
authors.initials: E
authors.lastname: Sosa
authors.affiliation: Centro de Desarrollo de Productos Bióticos, Instituto Politécnico Nacional, Carr. Yautepec-Jojutla km. 8.5, San Isidro, Yautepec Morelos 62731, Mexico.
authors.forename: L A
authors.initials: LA
authors.lastname: Bello-Pérez
authors.affiliation: Departamento de Preparatoria Agrícola, Universidad Autónoma Chapingo, Km 38.5 Carretera México-Texcoco, Texcoco 56230, Mexico.
authors.forename: E J
authors.initials: EJ
authors.lastname: Vernon-Carter
authors.affiliation: División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, Apartado Postal 55-534, Iztapalapa 09340, Mexico. Electronic address: jjar@xanum.uam.mx.
authors.forename: J
authors.initials: J
authors.lastname: Alvarez-Ramirez
mesh_terms: D058266:Dielectric Spectroscopy; D010084:Oxidation-Reduction; D010984:Platinum; D013213:Starch / Q000737:chemistry*
chemical_list: D010984:Platinum; D013213:Starch
keywords: Cyclic voltammetry; Electrochemical impedance spectroscopy; Electrolytic resistance; Gelatinized starch dispersions; Redox properties