INFLUENCE OF THE STRUCTURAL-CHANGES DURING ALKALINE COOKING ON THE THERMAL, RHEOLOGICAL, AND DIELECTRIC-PROPERTIES OF CORN TORTILLAS

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