Changes in the physicochemical properties of maize endosperm, endosperm fractions, and isolated starches because of nixtamalization

This work focused on the physicochemical changes undergone by maize endosperm during a thermo-alkaline nixtamalization process for the cooking (0 h) and steeping (8 h) steps. The study was performed on the outer-most 10%, subsequent 10%, and the remaining 80% of crude, cooked (0 h), and steeped (8 h) endosperm. Calcium content increased mainly in the outermost layers of the endosperm, while the remaining 80% showed no significant changes. The starch granules showed no external damage during cooking and steeping. X-ray analysis revealed that the hard endosperm contained A-type starch with an orthorhombic crystalline structure. Exami-nation of the isolated starches during nixtamalization showed that there is a fraction that does not undergo physicochemical transformation when in contact with water and heat, and this fraction can be referred to as resistance starch. A new methodology using scanning electron microscopy has shown that the pasting properties are determined by the changes in the morphology of the paste.

Automated summary

This study focused on the physiochemical changes in maize endosperm during a thermo-alkaline nixtamalization process. It was found that calcium content increased in the outer layers, starch granules showed no damage, and the pasting properties were influenced by the morphology of the paste.