The mass transport phenomenon through pericarp during the nixtamalization process

•We identified conditions for greater diffusion of alkaline solution into corn.•Maximum calcium content was detected in samples processed at high temperatures.•The mathematical model is useful to explain the transport of mass into corn.•Kinetic and structural changes in pericarp are crucial in nixtamalized products.

The aim of this study was to correlate the apparent diffusion coefficients with the morphological changes that take place in pericarp through the evaluation of cooking stage of corn grains, in order to set the process conditions, where the diffusion rate is faster to reduce time in nixtamalization process.In order to set the process conditions where the diffusion rate is greater to reduce the nixtamalización process time. The diffusion of calcium was studied at three temperatures (70, 80 and 90 °C). The cooking of the corn was conducted in a differential photoacoustic cell (DPC). Additionally, diffusion process was simulated in a modulated temperature differential scanning calorimeter (MDSC). After cooking, the residual calcium content in the pericarp was determined by atomic absorption spectroscopy (AAS). These data were used to solve the mathematical modeling. The diffusion model employed was developed using Fick's law in order to explain the transport of mass into the corn. The diffusion phenomenon was related to the morphological changes experienced by pericarp using the low-vacuum scanning electron microscopy technique (LV-SEM). The final apparent diffusion coefficients were 0.9265, 1.2101 and 1.4533 m2/s × 10−8 at 70, 80 and 90 °C respectively; then, the best process conditions recommended for cooking stage of QPM corn grains are 90 °C during 50 min.