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Changes in Nixtamalized Corn Flour Dependent on Postcooking Steeping Time

¹Thermoelectronic and Optical Properties Laboratories (TOP-Labs), Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada del I.P.N., José Siurob 10, Col. Alameda, Querétaro, México. C.P. 76040. ²Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Campus Juriquila, Apdo Postal 0-1010, Queretaro, Queretaro 76001, Mexico. ³Corresponding author: Phone: 52-4-2381141. E-mail: marioga@athena.fata.unam.mx ⁴Centro de Investigación en Ciencia Aplicada y Technología Avanzada del I.P.N., Legaria 694, Col. Irrigación, C. P. 11500, Mèxico D.F., Mexico. ⁵Instituto de Investigación en Materiales, Universidad Nacional Autónoma de México, Apdo. Postal 70-360, Ciudad Universitaria, C.P. 04410, México, D.F., Mexico.

We studied the effect of steeping time on various physical and chemical properties of maize flour prepared by the traditional nixtamalization process as well as in oversaturated calcium ion conditions. The calcium content of the corn flour was measured by atomic absorption spectroscopy and was correlated with X-ray diffraction, viscosity, and pH measurements. Calcium content of the flour showed a nonlinear dependence on steeping time, with a local calcium maximum occurring at ≈7 hr. The pH level of the corn flour increased with steeping time, thus roughly following the time trend shown by the steeping time dependence of the calcium content. Flour crystallinity and peak viscosity of water suspensions of the flour reached maximal values at ≈7–9 hr of steeping, in agreement with manufacturing experience showing that these are appropriate steeping times to prepare tortillas with the desirable rheological and organoleptic properties.