title: Determination of calcium mobility in alkaline-cooked grounded corn in presence of a magnetic field.
abstract: The mobility of calcium ions in corn dough prepared using commercial powder of alkaline-cooked grounded-corn kernel was determined in presence of a magnetic field. The ionic conduction was determined using 2 electrodes placed at 2 consecutives corners of the square samples: the excitation line was along one edge. Three different calcium concentrations [Ca] and 3 different magnetic field B conditions (B0, B-, B+) were analyzed; in all cases, the same amount of water was used. The relaxation times τ were determined by measuring the ionic current with and, immediately after, without excitation voltage. An empirical model, based on the obstruction effect characteristic of the ionic conduction and on the effect of the magnetic field B on the motion of the ions, was developed to explain the dependence of τ with [Ca] and B. The threshold concentration at which the Ca ions are not longer linked chemically to the starch molecules and move freely in the dough interior was obtained.
  
  
  CONCLUSIONS
  It was possible to determine the free-to-link threshold concentration for calcium ions in alkaline-cooked grounded-corn kernel dough; this is near 1.5% Ca. The magnetic field allows to separate and measuring different types of ions; a model to explain the dependence of the relaxation time with the magnetic field was included.
authors.affiliation: Centro de Fisica Aplicada y Tecnologia Avanzada, Univ. Natl. Autonoma de México, Campus Juriquilla, A.P. 1-1010, Querétaro, Qro, 76000, México.
authors.forename: S
authors.initials: S
authors.lastname: Vargas
authors.forename: D
authors.initials: D
authors.lastname: Rangel
authors.forename: F
authors.initials: F
authors.lastname: Quintanilla
authors.forename: R
authors.initials: R
authors.lastname: Rodriguez
mesh_terms: D002118:Calcium / Q000737:chemistry*; D003296:Cooking; D060526:Magnetic Fields; D013213:Starch / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry*
chemical_list: D013213:Starch; D002118:Calcium
keywords: alkaline cooking; free calcium; ionic conduction; linked calcium; magnetic field