Effect of wet grinding and drying of the nixtamal on physicochemical, morphologic and vibrational properties of flours and rheological changes of masa

Nixtamalization process conditions such as grinding and drying increases stiffness in the starch; consequently, swollen capacity, water binding capacity, and water solubility index decrease. These affect cohesion characteristics, flow behavior, and textural parameters of flour, masa, and tortilla. The aim of this study was to evaluate the changes in physicochemical, morphologic, and vibrational properties of flours and masa considering the variation of drying and milling conditions. Water absorption index and water solubility index changes are attributed to nixtamal wet grinding. Scanning electronic microscopy analysis showed starch granules with greater gelatinization. Pasting profile analysis and changes observed in IR spectra indicate that drying and grinding methods are influential in the quality of flours. The study of masa rheological parameters indicated that drying influenced masa viscoelasticity. These results showed that drying temperature and wet grinding of nixtamal are necessary conditions to obtain flour and masa and determine the quality of its products. PRACTICAL APPLICATIONS: Mills discs distance and nixtamal drying temperature are process conditions that influence physical, chemical, and structural changes of the starch, which modify the rheological behavior of flours and masa. Likewise, tortilla is a food of greater consumption among the Mexican population, and its textural quality depends on flour and masa quality.