J. Phys. IV France 125 (2005) 833-836
DOI: 10.1051/jp4:2005125192

The diffusion of calcium ion into the organic layers studied by a differential photoacoustic system

D.M. Hurtado-Castañeda^{1, 2}, J. Fernández^{1, 2}, E. Gutiérrez^{3, 4}, I. Rojas-Molina^{3, 5}, J.L. Fernández-Muñoz⁶ and M.E. Rodríguez<sup>2

1</sup>  Instituto tecnológico de Querétaro, Av. Tecnológico s/n, Querétaro, Mexico
²  Centro de Física Aplicada y Tecnología Avanzada de la UNAM, Querétaro, Querétaro, Mexico
³  Posgrado en Química, Facultad de Química de la UNAM, Mexico
⁴  FES Cuautitlan, UNAM, Cuautitlan, Mexico
⁵  Facultad de Ciencias Naturales, Lic. en Nutrición, UAQ, Querétaro, Qro, Mexico
⁶  CICATA-IPN, Unidad Legaria, Mexico, DF, Mexico

Abstract
Kinetics of water and calcium ion diffusion into biological layer (pericarp) exposed to different thermal treatments was investigated using the novel concept of differential photoacoustic cell (DPC). The latter enabled the real time measurements of amplitude and phase of PA signals originating from the reference and test samples. The uptake of calcium ion and water into kernel during the cooking of maize occurs predominantly through the pericarp. This process affects the physiochemical properties of kernel causing the corresponding changes of the signal and the phase of PA signal in time. The novel concept of DPC including temperature profiles is an excellent tool to study in-situ kinetics and thermal properties of material.

© EDP Sciences 2005