Model aanalyst 200

The mineral content (Cu, Zn, K, Fe and Na) was obtained from the ashes of the samples following the method by the AOAC with minor modifications. Flours and tortilla samples (5 g) were calcined in a muffle furnace (Felisa^®, Model FE-340, Guadalajara, Jalisco, México) for 8 h at 550 °C. Subsequently, 3 mL of HNO₃ (SCP^®, Quebec, Canada) (0.2%, v/v) was added and taken to dryness on a hot plate (100 °C). The samples were calcined again for 2 h at 550 °C until white ashes were obtained, 5 mL of 6 M HCl (JT Baker^®, Fisher Scientific, West Palm Beach, Florida, USA) were added and dried. Finally, 20 mL of HNO₃ (0.2%, v/v) (Merck^®, Toluca, Estado de México, Mexico) were added and samples were transferred into plastic conical tubes (Corning^®, Merck, Toluca, Estado de México, México). The samples were analyzed using atomic absorption spectroscopy (Perkin Elmer^®, Model AAnalyst 200, Madrid, Spain) with acetylene flame adjusting the wavelength for each mineral [12 ].

Iron, zinc, and calcium content were determined following the procedure described by Lazarte, Carlsson, et al. (2015)) Minerals were analyzed by flame atomic absorption spectrophotometry with air–acetylene flame (Model AAnalyst 200; PerkinElmer Corp.) at 248.3 nm for iron, 213.9 nm for zinc, and 422.7 nm for calcium.