title: Acid hydrolysis of native corn starch: morphology, crystallinity, rheological and thermal properties.
abstract: The acid hydrolysis of native corn starch at 35 °C was monitored during 15 days. After this time, the residual solids were about 37.0 ± 3.0%. First-order kinetics described the hydrolysis data, giving a constant rate of kH = 0.18 ± 0.012 days(-1). Amylose content presented a sharp decrement of about 85% and X-ray diffraction results indicated a gradual increase in crystallinity during the first 3 days. SEM micrographs showed that hydrolysis disrupted granule morphology from an initial regular shape to increasingly irregular shapes. Fractal analysis of SEM images revealed an increase in surface roughness. Fast changes in the thermal effects were caused by molecular rearrangements after fast hydrolysis of amylose in the amorphous regions in the first day. Steady shear rate and oscillatory tests showed a sharp decrease of the apparent viscosity and an increase of the damping factor (tan(δ)) caused by amylose degradation.
authors: Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Ingeniería de Procesos e Hidráulica, Apartado Postal 55-534, México, D.F. 09340, Mexico; Centro de Desarrollo de Productos Bióticos (CEPROBI) del Instituto Politécnico Nacional, Yautepec, Morelos, Mexico.
authors: R G
authors: RG
authors: Utrilla-Coello
authors: Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Ingeniería de Procesos e Hidráulica, Apartado Postal 55-534, México, D.F. 09340, Mexico.
authors: C
authors: C
authors: Hernández-Jaimes
authors: Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Ingeniería de Procesos e Hidráulica, Apartado Postal 55-534, México, D.F. 09340, Mexico.
authors: H
authors: H
authors: Carrillo-Navas
authors: Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Ingeniería de Procesos e Hidráulica, Apartado Postal 55-534, México, D.F. 09340, Mexico.
authors: F
authors: F
authors: González
authors: Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Ingeniería de Procesos e Hidráulica, Apartado Postal 55-534, México, D.F. 09340, Mexico.
authors: E
authors: E
authors: Rodríguez
authors: Centro de Desarrollo de Productos Bióticos (CEPROBI) del Instituto Politécnico Nacional, Yautepec, Morelos, Mexico.
authors: L A
authors: LA
authors: Bello-Pérez
authors: Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Ingeniería de Procesos e Hidráulica, Apartado Postal 55-534, México, D.F. 09340, Mexico.
authors: E J
authors: EJ
authors: Vernon-Carter
authors: Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Ingeniería de Procesos e Hidráulica, Apartado Postal 55-534, México, D.F. 09340, Mexico. Electronic address: jjar@xanum.uam.mx.
authors: J
authors: J
authors: Alvarez-Ramirez
keywords: Acid hydrolysis; Corn starch; Crystallinity; Kinetics; Morphology