Influence of the structural changes during alkaline cooking on the thermal, rheological, and dielectric properties of corn tortillas.

Abstract

Basic data on thermal, dielectric, and infrared spectra properties of cooked tortillas were investigated with the aim of understanding the role of lime, Ca(OH)(2), that is incorporated during the alkaline cooking process. The data are further supplemented by X-ray diffraction and texture measurements. The changes in the thermal diffusivities, as measured by the photoacoustic technique, as well as changes in texture, X-ray patterns, dielectric, and infrared spectra properties are presented as a function of the lime concentration. The results show strong evidence that there is a marked concentration of lime at approximate to 0.2% above and below where there are different behavior patterns of the measured properties of tortilla. In particular, the results of the study of dielectric constants and thermal diffusivity provide strong evidence for an enhancement of the starch crosslinking taking place at a lime content of approximate to 0.2%.