Effects of a Low-Shear Transport System on the Physicochemical Characteristics of Nixtamal Corn Flour

Abstract

Extrusion is considered a high potential technology in the production of nixtamal corn flour (NCF); however, shear force and high temperature produce starch dextrinization, modifying the quality characteristics of NCF. This investigation evaluated the effect of feed moisture, temperature, calcium hydroxide and speed in a low-shear transport system (LSTS) on water absorption index (WAI), water solubility index (WSI), relative viscosity, pH and color of NCF. Feed moisture and temperature had a significant effect on most of the characteristics of the NCF, while speed of transport and calcium hydroxide did not. NCF obtained from the LSTS presented a higher WAI and a lower WSI, relative viscosity and luminosity than NCF produced by the traditional method; however, differences between them were not significant. Lack of difference in WSI between NCF produced by both methods indirectly show that LSTS produces a low dextrinization. Practical Applications The most common corn food products elaborated from nixtamal corn flour (NCF) are snacks, tortilla, porridge and tamal. The low-shear transport system (LSTS) may be used to produce NCF appropriate for any of these final products surpassing the extrusion-cooking process, which is mainly used to produce snacks. According to the results of this investigation, it is possible to use LSTS to obtain NCF with a lower degree of dextrinization, improving NCF quality.